Impacts of Rearing Enrichments on Pullets and Free-Range Hens’ Positive Behaviors across the Flock Cycle

Effect of different pasture species on welfare and behavior of slow-growing broiler chickens in free-range production system

This study investigated the effect of various pasture species on the welfare and behavior of slow-growing broiler chickens in the free-range production system. After 21 days completely indoors, the birds were permitted access to outdoor pens cultivated with one of the following pasture treatments: Medicago sativa (A), Trifolium repens (WC), Lolium perenne (PR), and a mixture (Mix, A + WC + PR). The range availability was restricted between 08:30 and 16:30 daily. It was found that pasture type had a significant effect on the fluctuating asymmetry of the face and radius length (P < 0.01). Duration of tonic immobility and blood parameters did not differ among the pasture species and between sexes at 11 weeks of broiler age (P > 0.05). Pasture treatment had no significant effect on broiler behaviors (P > 0.05). However, the age of broilers had a significant effect on pecking, dustbathing, and scratching (P < 0.01). Pecking behavior was affected by the time of the day; morning and afternoon (P < 0.01). Location had a significant effect on pecking and stretching behaviors (P < 0.01). In the study, dustbathing behavior was significantly affected by the interaction between location and age (P < 0.01), age and time of the day (P < 0.01), and location, age, and time of the day (P < 0.05). Scratching behavior was significantly affected by the interaction between location and time of the day (P < 0.05) and location, age and time of the day (P < 0.01). Stretching behavior was significantly affected by the interaction between location and age (P < 0.05) and location, age and time of the day (P < 0.05). It was concluded that access to the studied pasture species does not affect the evaluated welfare traits and observed behaviors. Therefore, it is suggested that other pasture species should be investigated to identify their effect on slow-growing strains in the free-range production system.

Enhancing their quality of life: environmental enrichment for poultry

Providing environmental enrichments that increase environmental complexity can benefit poultry welfare. This Poultry Science Association symposium paper is structured around four themes on 1) poultry preferences and affective states 2) species-specific behavior, including play behavior and the relationship between behavior, activity level and walking ability, 3) environmental enrichment and its relationship with indicators of welfare, and 4) a case study focusing on the application of enrichments in commercial broiler chicken production. For effective enrichment strategies, the birds' perspective matters most, and we need to consider individual variation, social dynamics, and previous experience when assessing these strategies. Play behavior can be a valuable indicator of positive affect, and while we do not yet know how much play would be optimal, absence of play suggests a welfare deficit. Activity levels and behavior can be improved by environmental modifications and prior research has shown that the activity level of broilers can be increased, at least temporarily, by increasing the environmental complexity. However, more research on impacts of enrichments on birds' resilience, on birds in commercial conditions, and on slow(er)-growing strains is needed. Finally, incorporating farmers' expertise can greatly benefit enrichment design and implementation on commercial farms.

Cecal Microbiota of Free-Range Hens Varied With Different Rearing Enrichments and Ranging Patterns

Free-range pullets are reared indoors but the adult hens can go outside which is a mismatch that may reduce adaptation in the laying environment. Rearing enrichments might enhance pullet development and adaptations to subsequent free-range housing with impact on behavior and health measures including gut microbiota. Adult free-range hens vary in range use which may also be associated with microbiota composition. A total of 1,700 Hy-Line Brown^® chicks were reared indoors across 16 weeks with three enrichment treatment groups: “control” with standard litter housing, “novelty” with weekly changed novel objects, and “structural” with custom-designed perching structures in the pens. At 15 weeks, 45 pullet cecal contents were sampled before moving 1,386 pullets to the free-range housing system. At 25 weeks, range access commenced, and movements were tracked via radio-frequency identification technology. At 65 weeks, 91 hens were selected based on range use patterns (“indoor”: no ranging; “high outdoor”: daily ranging) across all rearing enrichment groups and cecal contents were collected for microbiota analysis via 16S rRNA amplicon sequencing at V3-V4 regions. The most common bacteria in pullets were unclassified Barnesiellaceae, Prevotella, Blautia and Clostridium and in hens Unclassified, Ruminococcus, unclassified Lachnospiraceae, unclassified Bacteroidales, unclassified Paraprevotellaceae YRC22, and Blautia. The microbial alpha diversity was not significant within the enrichment/ranging groups (pullets: P ≥ 0.17, hen rearing enrichment groups: P ≥ 0.06, hen ranging groups: P ≥ 0.54), but beta diversity significantly varied between these groups (pullets: P ≤ 0.002, hen rearing enrichment groups: P ≤ 0.001, hen ranging groups: P ≤ 0.008). Among the short-chain fatty acids (SCFAs), the propionic acid content was higher (P = 0.03) in the novelty group of pullets than the control group. There were no other significant differences in the SCFA contents between the rearing enrichment groups (all P ≥ 0.10), and the ranging groups (all P ≥ 0.17). Most of the genera identified were more abundant in the indoor than high outdoor hens. Overall, rearing enrichments affected the cecal microbiota diversity of both pullets and adult hens and was able to distinguish hens that remained inside compared with hens that ranging daily for several hours.