Welfare issues associated with moulting of laying hens

A practice that is used to extend the period of lay of hens is induced moulting. It involves restriction of nutrients, and sometimes manipulation of lighting, with the consequent loss of bodyweight and feathers, regression of the reproductive tract and cessation of egg lay. When the period of moulting is completed, the reproductive tract will regenerate and egg production will resume, thereby extending the overall period of lay. Towards the end of the laying cycle of hens, the production and quality of eggs decline. At this point, some egg farmers will induce a moult in the flocks to reduce bird-replacement costs and improve profitability. In the Australian egg industry, less than 10% of layers are moulted. There are implications for the welfare of hens that are induced to moult, particularly due to loss of bodyweight and feathers. Histopathological studies have shown the extent to which loss of feathers may affect welfare from a physical perspective, and it terms of pain. It is apparent that induced moulting can lead to an increase in aggression and injurious pecking, and birds with poor feather cover are vulnerable to damage from this pecking. Induced moulting can increase stress, although the implications of this for the welfare of hens is not well understood. The endocrine events associated with induced moulting are reasonably well known and it is possible to manipulate the endocrine system to extend the lay of hens without the need to moult. Nevertheless, these approaches are unlikely to be adopted into practice. More importantly, hens should always have feed and water available and are in good condition before undergoing a moult. This is essential from the perspective of ensuring adequate standards of welfare of birds.

Species composition and dispersal of nuisance flies breeding on egg farms in southern Australia

The vectorial and dispersal capacities of flies make them a biosecurity and food safety risk on egg farms. The design of optimal control and biosecurity programs requires knowledge of species composition and patterns of abundance of the fly populations present. Although there have been many studies of flies breeding on egg farms in other countries there is little information available in Australia. We monitored numbers and species of flies breeding on cage egg farms in southern Australia and used mass marking with fluorescent resin dye to assess the dispersal of the major species from one of the farms. The main peak in fly numbers occurred in spring and early summer and was comprised predominantly of little house flies (Fannia canicularis). Significant numbers of false stable flies (Muscina stabulans) were trapped near accumulated manure, but relatively low numbers were present in bird housing areas. House flies (Musca domestica) were found in only low numbers or were absent at most times of the year. In the dispersal studies, 85% of marked F. canicularis and 67% of marked M. stabulans were trapped within 255 m of the layer sheds. The greatest distance from the farm at which marked F. canicularis flies were captured was 739 m for traps and 1.25 km for tapes whereas M. stabulans flies were trapped at all distances including in the most distant trap nearly 2 km from the farm. Modelling of trap catches by distance predicted maximum dispersal distances of 1.6 km for F. canicularis and 2.4 km for M. stabulans.

Nutrient utilisation in grower pigs fed a protein concentrate blended with sweet potato roots either boiled or ensiled with or without vines

Blending sweet potato (Ipomoea batatas L. (Lam)) with a protein concentrate for pig feed is a common strategy used by small-scale livestock farmers across Africa, Asia and the Pacific. However, high dietary fibre in sweet potato (SP) forage may reduce nutrient utilisation and energy metabolism and reduce the growth rate of young pigs. A 32-day metabolic trial with grower pigs using a 4 × 4 Latin square design tested the hypothesis that there would be no difference in apparent total tract digestibility (ATTD) of nutrients, energy and nitrogen (N) balance in 25 kg grower pigs (Large White × Landrace × Duroc) fed diets based on a blend of 43–40% protein supplement with 57–60% of DM as SP roots either boiled (BR43) or ensiled alone (ER43) or ensiled with vines (ERV40). Blended SP diets provided ~14–15% crude protein (CP), 16.1–16.3 MJ digestible energy (DE)/kg DM and 0.54–0.58 g lysine/MJ DE. The control diet (STD) contained 16.5% CP, 14.8 MJ DE/kg DM, 0.58 g lysine/MJ DE. The major findings were as follows: (1) DM intake was higher (P < 0.05) for BR43 than ER43, ERV40 and STD diets, which were similar; (2) DM ATTD and energy utilisation were higher (P < 0.05) in pigs fed SP diets; (3) carbohydrate (N-free extracts) ATTD was higher (P < 0.05) in pigs fed BR43 and ER43 diets, while CP ATTD of both these diets was similar to that of STD and higher than that of ERV40; (4) ATTD of fats (ether extracts), CP, carbohydrates (N-free extracts) and total phosphorus was lower (P < 0.05) on ERV40, but fibre ATTD was higher; (5) N intake and N retained were similar (P > 0.05) for pigs fed BR43, ER43 and STD diets but lower for ERV40 (P < 0.05). Boiled or ensiled SP roots provided high nutrient and energy utilisation in growing pigs, but the inclusion of SP vines lowered ATTD, energy utilisation and N retained from the mixed diet (ERV40). It is concluded that boiled or ensiled SP root are equally valuable as blended feed for grower pigs. However, at 30%DM, ensiled SP vine in blended feed led to reduced grower-pig performance.

Free range hens use the range more when the outdoor environment is enriched

To evaluate the role of using forage, shade and shelterbelts in attracting birds into the range, three trials were undertaken with free range layers both on a research facility and on commercial farms. Each of the trials on the free range research facility in South Australia used a total of 120 laying hens (Hyline Brown). Birds were housed in an eco-shelter which had 6 internal pens of equal size with a free range area adjoining the shelter. The on-farm trials were undertaken on commercial free range layer farms in the Darling Downs in Southeast Queensland with bird numbers on farms ranging from 2,000-6,800 hens. The first research trial examined the role of shaded areas in the range; the second trial examined the role of forage and the third trial examined the influence of shelterbelts in the range. These treatments were compared to a free range area with no enrichment. Aggressive feather pecking was only observed on a few occasions in all of the trials due to the low bird numbers housed. Enriching the free range environment attracted more birds into the range. Shaded areas were used by 18% of the hens with a tendency (p = 0.07) for more hens to be in the paddock. When forage was provided in paddocks more control birds (55%) were observed in the range in morning than in the afternoon (30%) while for the forage treatments 45% of the birds were in the range both during the morning and afternoon. When shelterbelts were provided there was a significantly (p<0.05) higher % of birds in the range (43% vs. 24%) and greater numbers of birds were observed in areas further away from the poultry house. The results from the on-farm trials mirrored the research trials. Overall 3 times more hens used the shaded areas than the non shaded areas, with slightly more using the shade in the morning than in the afternoon. As the environmental temperature increased the number of birds using the outdoor shade also increased. Overall 17 times more hens used the shelterbelt areas than the control areas, with slightly more using the shelterbelts in the afternoon than in the morning. Approximately 17 times more birds used the forage areas compared to the control area in the corresponding range. There were 8 times more birds using a hay bale enriched area compared to the area with no hay bales. The use of forage sources (including hay bales) were the most successful method on-farm to attract birds into the range followed by shelterbelts and artificial shade. Free range egg farmers are encouraged to provide pasture, shaded areas and shelterbelts to attract birds into the free range.

A survey of village poultry production in the Solomon Islands

A total of 84 farmers in 31 villages of Guadalcanal, Western, Malaita and Central Provinces of the Solomon Islands were surveyed to obtain baseline information on the current feeding practices and farmer attitudes to village poultry production. Farming of village chickens in the Solomon Islands is conducted on a small scale. Most surveyed farmers thought chickens were easy to care for, provide food for the family and was a good cash income enterprise. Some farmers were interested in keeping local chickens, but found it difficult to obtain the birds. The main feed sources are fresh coconut, copra meal, fish meal, mill run, food scraps and forage sources from the range. Some villagers believe that chickens only need to eat household scraps and did not provide drinking water. Many villagers lacked the knowledge of managing a village poultry enterprise. Some chicken houses were built by using bush materials or by purchasing construction materials. Farmers indicated they would like the government to provide funds for establishing a smallholder poultry enterprise and to provide information on feeding and management of birds.

Husbandry of ratites and potential welfare issues: a review

Since the mid-1980s, there has been worldwide farming of ratites, particularly with ostriches, emus and rheas for feathers, meat, skin and oil. Most of these ratites are produced commercially outside their native habitat. This has raised concerns about welfare, particularly whether birds are provided the five freedoms: food and water; shelter; health care; alleviation of pain and suffering; and the freedom of movement. This paper reviews the factors that influence bird welfare before hatch with breeder, egg and hatchery management and after hatch with brooding and rearing systems, stocking density, handling, transport, disease and slaughter. Assessment of bird welfare in each of the production sectors in the industry is based on how well the five freedoms are being met. The review identifies egg handling practices and hatchery hygiene that can have a major impact on the subsequent health of hatched chicks. In addition, feeding of appropriate diets, reducing stocking density and improving housing can improve bird health and freedom of movement. When the husbandry practice of toe trimming is not practiced according to the best practice method, chronic pain may result and impair walking ability of birds. Stress and injuries to birds can be reduced when birds are handled correctly on farm and in the lairage and are transported using appropriate vehicles. Farmers, transporters and abattoir staff can have a major impact on maintaining bird welfare if best practice farming systems and husbandry practices are implemented.

Effect of diets with different energy and protein levels on performance of grower ostriches

Grower ostriches that are fed more expensive diets with high energy and high protein to maximise growth can exhibit health problems. Despite this there is an ‘industry view’ that birds can be grown to slaughter weight within 8 months when high energy and protein diets are used, rather than 12–14 months using conventional diets. Given this scenario it is likely that there would be lower total feed costs associated with feeding a high energy and high protein diet for only 8 months compared with feeding a traditional diet for 12–14 months. The purpose of this experiment was to conduct an on-farm trial with grower ostriches (liveweight 48.7–50.0 kg) housed in a feedlot to examine their performance when subjected to four dietary treatments fed over 4 weeks: (i) treatment 1: birds fed a commercial grower diet with 10.7 MJ/kg and 138.0 g/kg of protein; (ii) treatment 2: birds fed a low energy (10.0 MJ/kg) and low protein (126.0 g/kg) diet; (iii) treatment 3: birds fed a high energy (12.5 MJ/kg) and medium protein (136.0 g/kg) diet; and (iv) treatment 4: birds fed a high energy (12.5 MJ/kg) and high protein (143.0 g/kg) diet in a feedlot. Birds fed on the low energy and low protein diet had the highest feed intake compared with the other treatments. Birds on treatment 2 also had a significantly higher (P = 0.01) daily weight gain (277.3 g/bird) compared with treatment 1 (50.9 g), treatment 3 (49.1 g) and treatment 4 (32.0 g), respectively. The results indicate that better daily bodyweight gain is likely if ostrich growers are fed with a lower energy and lower protein diet.

Effects of modifying layer cages with perches on stress physiology, plumage, pecking and bone strength of hens

Summary. This experiment evaluated the welfare of layer hens housed in cages modified with perches. Welfare was assessed on the basis of physiological measures of stress (corticosterone concentrations ‘at rest’ and in response to ACTH and heterophil : lymphocyte ratios) and immunological responsiveness, feather condition and cover, bone strength, claw length and between-bird pecking behaviour. Factors examined were cage modification (perches v. standard cage), tier (upper v. lower), birds (1 or 2 birds/cage) and age (commencing at 35 v. 60 weeks of age). The cages provided a floor area of 1504 cm2 . Floor pens (2.5 by 2.5 m) with 10 birds/pen served as an external control treatment. Perches improved the strength of the femur (P<0.05) compared with standard cages but bone strength was still less than in floor pens (P<0.05). There were no effects of cage modification on any of the physiological variables or liveweight (P>0.05). The only improvement in feather condition and cover within cages due to the presence of a perch was in the condition of the tail feathers which was better (P<0.05) than in a standard cage, but not as good as tail feathers in the pen treatment (P<0.001). Overall, feather condition and cover was better in the pen treatment (P<0.001) and similar in the 2 cage treatments (P>0.05). The presence of a perch resulted in longer claws than in a standard cage and floor pens (P<0.05), and significant (P<0.01) perching activity compared with floor pens. The experiment showed that perches should be considered for use in commercial laying cages as they resulted in an improvement in bone strength; there was also an improvement in tail feather condition, which is considered by some to be an advantage.

Effects of modifying layer cages with solid sides on stress physiology, plumage, pecking and bone strength of hens

Summary. This experiment evaluated the welfare of layer hens housed in cages modified with solid sides. Welfare was assessed on the basis of physiological measures of stress [corticosterone concentrations ‘at rest’ and in response to adrenocorticotrophic hormone (ACTH) and heterophil : lymphocyte ratios)] and immunological responsiveness, feather condition and cover, bone strength, claw length and between-bird pecking behaviour. Factors examined were cage modification (solid sides v. open sides i.e. standard cages), tier (upper v. lower), birds (1 or 2 birds/cage) and age (commencing at 35 v. 60 weeks of age). The cages provided a floor area of 1504 cm2. Floor pens (2.5 by 2.5 m) with 10 birds/pen served as an external control treatment. Solid sides in cages reduced the level of stress, compared with both standard cages and floor pens, based on lower corticosterone concentrations (2.2 v. 3.4 and 4.4 nmol/L, respectively) and lower heterophil : lymphocyte ratios (1.36 v. 1.66 and 1.66, respectively) (P<0.05). The ACTH response data reflected a lower level of stress in the solid side compared with the pen treatment (P<0.05). Feather condition and cover were improved by the presence of solid sides compared with standard cages (P<0.05), were similar to the floor pen treatment and were probably a consequence of reduced pecking behaviour both within (65%) and between cages (86%) (P<0.05). Solid sides had no effects on immunological responsiveness, claw length or bone strength. The experiment showed that solid sides can have a positive effect on welfare by reducing the level of stress, decreasing between-bird pecking and improving feather condition and cover. However, another study showed mortalities increased in cages with solid sides during hot weather.

The absence of neuromas in beaks of adult hens after conservative trimming at hatch

OBJECTIVE

To determine the effects of the amount of break removed and cauterisation time on neuroma formation in hens.

DESIGN

A pathology study with controls.

ANIMALS

Twenty domestic fowl were beak-trimmed. Three non-beak-trimmed domestic fowl were used as controls.

PROCEDURE

Beaks of two age groups with two levels of beak removal and either 2 s or 4 s cauterisation, were investigated macroscopically and microscopically for deformities.

RESULTS

Scattered trauma-associated neuromas were present in the beaks of pullets 10 weeks after moderate trimming at hatch. Neuromas were not present in beaks of adult hens that had been similarly trimmed. Sensory corpuscles were present 10 and 70 weeks after moderate trimming, though fewer in number than in intact control hens. In contrast, trauma-associated neuromas persisted in beaks of 70-week-old hens that had been severely trimmed at hatch. A range of deformities that were absent in moderately trimmed hens, were observed in hens with severely trimmed beaks. Receptors were not seen in severely trimmed beaks.

CONCLUSION

Beak-trimming at hatch induces the formation of neuromas, regardless of the amount of tissue removed. There is a critical amount of beak tissue that can be removed, beyond which trauma-associated neuromas will not resolve, but will persist in mature hens.

Effect of perches and solid sides on production, plumage and foot condition of laying hens housed in conventional cages in a naturally ventilated shed

The effect of modified cages on production, shell quality, feather cover and foot condition was measured in 2 Australian commercial laying strains housed in a naturally ventilated laying shed from 18 to82 weeks of age. Two cage modifications were investigated. Firstly , the inclusion of a perch within the cage, and secondly, the installation of solid sides. Compared with normal cages, installation of a perch in a cage reduced food intake (5.3%) and liveweight (4.5% at 82 weeks) and improved feather cover around the vent (feather score of 2.15 to 2.66). This was offset by a decrease in egg production (2.4%), shell weight (1.5%) and thickness (11%), an increase in cracked (53.8%) and dirty eggs (28.9%), and an increase in claw length (9.2%). Relative to control cages, the provision of solid sides in cages improved overall feather cover of hens (feather score of 2.46 to 2.67), but there was a 54.5% increase in hen mortality during a period of hot weather. Additional modifications to the cage are required to optimise the benefit of perches. Similarly, improvement in ventilation and cooling in naturally ventilated sheds are required to maximise the benefits of solid-sided cages for hens and avoid heat stress.

Production and heart rate responses of chickens beak-trimmed at hatch or at 10 or 42 days of age

Heart rate was monitored before and after beak trimming in restrained chickens to measure responses to beak trimming at hatch and at 10 and 42 days of age. Immediately after trimming chickens sham-trimmed (control) and trimmed at 10 and 42 days of age had an increase in heart rate, with the 42-day-old chickens showing the greater change. Chickens sham-trimmed and trimmed at hatch showed no change in heart rate. No difference between trimmed and sham-trimmed chickens occurred at any age for heart rate response. These data indicate that heart rate at trimming may be inadequate as a measure of the stress response associated with beak trimming, especially with the concurrent stressors of handling and restraint. Beak trimming and handling of chickens at hatch is either less stressful than trimming at 10 and 42 days of age, as indicated by the lack of a heart rate response, or heart rate is already at a maximum in chickens at hatch, due to stress associated with hatching. Food intake and body weight were measured for 3-4 weeks after trimming to assess the longer term effects of age and level of trimming on performance of the chicken. Removal of 3 mm of beak at hatch or 4.5 mm at 10 days of age depressed feeding levels and a reduced body weight, indicative of a chronic stress associated with beak trimming.

Effect of age of beak trimming on the production performance of hens

The effect of age at beak trimming (at hatch, or 10 or 42 days) on the production performance of 2 Australian commercial laying strains (brown egg and a tinted egg layer) was assessed by measuring egg production, food intake, food efficiency, egg weight, egg gradings and body weights of chickens from 19 to 82 weeks of age. Beak trimming removed one half of the upper beak and one third of the lower beak from birds. The tinted egg strain trimmed at hatching was the most efficient of all treatment groups. Layers not trimmed consumed significantly more food, laid fewer eggs and had poorer food efficiency than beak trimmed birds. Early in lay there was no difference in daily egg production with age at beak trimming, but by 50 weeks of age, birds trimmed at hatching or 42 days were producing more eggs than those trimmed at 10 days of age. Chickens trimmed at hatching consumed less food than chickens trimmed at 10 days, and in the late laying phase (67-82 weeks) all beak trimmed groups had significantly lower food intake than control hens. These results show that age of beak trimming influences performance and that considerable saving in food costs for the Australian Poultry Industry can be achieved by trimming half of the top beak and one third of the bottom beak of chickens at hatching.

Effects of beak trimming and restraint on heart rate, food intake, body weight and egg production in hens

1. Heart rate (measured on restrained hens in two experiments) was used as an indicator of short term fear and pain responses of light and heavy strains of hens subjected to beak trimming. 2. In the first experiment 3 mm of the upper and lower mandibles was trimmed, while in the second 0, 2, 4, 6 and 8 mm of upper and lower mandibles were removed. 3. Production responses to beak trimming were measured after trimming, for 4 weeks in experiment 1 and for 10 weeks in experiment 2. 4. In the first experiment the recovery of beak trimmed hens to normal heart rate took significantly longer than that of control hens subjected only to catching and restraint, suggesting that there was short term pain associated with beak trimming. 5. The heavier strain took about 4 min longer to return to a normal heart rate than the lighter strain, indicating a strain difference in responsiveness to beak trimming. 6. Trimming the hens' beak by 3 mm had no significant effect on rate of lay or body weight, but their mean egg weight was depressed and food intake took 9 to 10 d to recover to pre-trimming values. 7. In the second experiment a plateau was reached in recovery time of the heart rate once 4 mm of beak was removed. Removal of 4, 6 and 8 mm of beak depressed normal feeding and resulted in variable effects on production and body weight.