Contrafreeloading and foraging-related behavior in hens differing in laying performance and phylogenetic origin

Food Grinding Behavior: A Review of Causality and Influential Factors

Food waste is a common issue arising from grinding of food by experimental animals, leading to excessive food scraps falling into cages. In the wild, animals grind food by gnawing vegetation and seeds, potentially damaging the ecological environment. However, limited ecology studies have focused on food grinding behavior since the last century, with even fewer on rodent food grinding, particularly recently. Although food grinding's function is partially understood, its biological purposes remain under-investigated and driving factors unclear. This review aims to explain potential causes of animal food grinding, identify influencing factors, and discuss contexts and limitations. Specifically, we emphasize recent progress on gut microbiota significance for food grinding. Moreover, we show abnormal food grinding is determined by degree of excess normal behavior, emphasizing food grinding is not meaningless. Findings from this review promote comprehensive research on the myriad factors, multifaceted roles, and intricate evolution underlying food grinding behavior, benefiting laboratory animal husbandry and ecological environment protection, and identifying potential physiological benefits yet undiscovered.

Laying Hens: Why Smothering and Not Surviving?-A Literature Review

The proliferation of rearing systems providing opportunities for birds to engage in natural behaviors can trigger behavioral repertoires that when not manageable compromise animal welfare and the economic viability of the flock. Smothering in laying hens has long been perceived as "natural" or the result of hysteria among birds in the flock. However, the current literature has recognized smothering as an abnormal outcome with the potential to result in significant losses in cage-free poultry systems. Recent studies have specifically aimed to categorize the organization of smothering behavior and highlight its potential causes and consequences. In this study, literature review and bibliographic mapping, drawing on published articles and engagement with poultry farmers through extension and rural technical assistance, were employed. The findings indicate that smothering is a behavior triggered by factors related to the environment in which the laying hens are kept. This study concludes that there is a critical need for more rigorous and detailed research to elucidate the nuances of avian behavioral physiology and assess the impact of production systems on animal welfare and the economic impacts on the flock. This research contributes to a deeper understanding of bird behavior in high-production environments and provides practical insights for the poultry industry.

Domestic pet dogs (Canis lupus familiaris) do not show a preference to contrafreeload, but are willing

Contrafreeloading is the behavior of working for food when also provided with identical food that does not require effort to obtain. This behavior has been observed in humans and non-human animals, including domesticated species. In the current investigation, we assessed whether companion animals, specifically domestic dogs, contrafreeload when presented with two feeders simultaneously, a snuffle mat (a work for food device) and a tray (a freely available food device). Thirty-eight pet dogs participated in the study in which ten feeding trials were presented where food was distributed equally in both feeders. Three overarching research questions were considered: (1) Do dogs prefer to contrafreeload and/or are they willing to contrafreeload, (2) is activity (step count) or body condition score (BCS) related to contrafreeloading behavior and, (3) does previous experience with puzzle feeders impact contrafreeloading behavior? Two general linear models were conducted assessing the effects of sex, experience, age, activity and BCS on the proportion of first choices to the snuffle mat (ICs) and the number of interactions with the snuffle mat while food was still available in the tray (INs). Overall, when assessing the proportion of first choices to each feeder, dogs demonstrated a willingness to contrafreeload but not a preference to contrafreeload. In a reduced model, only one term, owner-reported body condition score, had a significant effect, suggesting that dogs with a higher BCS demonstrated a greater proportion of first choices for the snuffle mat (F (1,36) = 7.72, p = 0.009, η2p = 0.177). In evaluating the number of interactions with the snuffle mat while food was still available in the tray, the model was not significant (F (5,29) = 1.231, p = 0.320, η2p = 0.175). This study represents the first investigation of contrafreeloading in domestic pet dogs and informs recommendations for canine enrichment.

Contrafreeloading Indicating the Behavioural Need to Forage in Healthy and Feather Damaging Grey Parrots

Contrafreeloading (CFL) is a concept that describes the preference of an animal to work for food even when identical food is freely available, and reflects an intrinsic motivation to engage in foraging-related activities. However, altered brain neurochemistry, which can be induced by chronic exposure to a suboptimal living environment, may affect this intrinsic motivation in animals with abnormal repetitive behaviours (ARBs), including parrots with feather damaging behaviour. To determine whether this was the case, we evaluated CFL activity in healthy (n = 11) and feather damaging (n = 10) Grey parrots (Psittacus erithacus) by offering them a free choice to obtain identical food from a food bowl or from a foraging device. Differences in CFL activity were observed, with feather damaging Grey parrots displaying less CFL (as indicated by shorter foraging times and lower amounts of food consumed from the foraging devices) compared to healthy conspecifics, indicating altered 'motivation' and time allocation, for which the underlying mechanism needs to be clarified further. Nevertheless, despite the variable level, all birds displayed CFL, which, together with a seemingly positive correlation between CFL activity and the plumage condition of the birds, suggests that parrots are intrinsically motivated to forage and highlights the importance of providing foraging opportunities to captive parrots.

Oviduct Histopathology of Internal Laying and Egg-Bound Syndrome in Laying Hens

In the egg industry, common reproductive disorders, such as internal laying and egg-bound syndrome, not only reduce egg productivity but also cause deaths in severe cases. In this study, we focused on the oviduct histology of the pathogenesis of internal laying and egg-bound syndrome. We divided the aged laying hens into four groups according to the observation of the abdominal cavity and oviductal lumen: healthy, internal laying, egg-bound, and intercurrent. The percentages of healthy, internal laying, egg-bound, and intercurrent groups were 55%, 17.5%, 15%, and 12.5%, respectively. In all parts of the oviduct (i.e., infundibulum, magnum, isthmus, and uterus), the oviductal epithelium was composed of ciliated epithelial cells and secretory cells. The epithelial region lacking cilia was larger in the entire oviduct of the internal laying, and intercurrent groups than in the healthy group. In the internal laying, egg-bound, and intercurrent groups, significant T-cell infiltration was observed in the lamina propria of the entire oviduct. The morphological alteration of ciliated epithelial cells in the oviducts caused by inflammation may be the underlying cause of the pathogenesis of internal laying and egg-bound syndrome.