Animal lives worth living

Abstract

Damaging behaviours in pigs and laying hens are among the most concerning current welfare issues. They are multifactorial in origin and difficult to stop once occurring. Prevention is crucial, and this is the focus of the COST Action project ‘GroupHouseNet’. In laying hens, feather pecking (FP) can best be prevented at the hatchery. The parental stock’s predisposition for FP can be assessed by epigenetic analysis, allowing careful stock selection. The fertilized eggs are then conventionally incubated in the dark, but studies show that light provision may reduce FP. Recent development of in-ovo sexing reduces chick handling, thus reducing stress. It further allows hatching with food and water provision, enabling on-farm hatching. Accessing feed right after hatching can be crucial for chicks to learn what to peck and eat. Artificial dark brooders, mimicking the mother hen’s wings, reduce fear, stress and FP. Matching the rearing and laying system through an all-in-all-out system reduces stress by eliminating catching, handling, transport and changing environment. In practice, multiple all-in-all-out barns can provide continuous egg output. A sustainable and circular system of feeding chickens insects grown using chicken manure seems feasible and positive in preventing FP. The use of pasture and supplementing hens whole grains are also being researched as potential strategies. Together, these trends can help in preventing damaging FP in laying hens. For pigs, early life factors can also influence later damaging behaviour, such as aggression, tail and ear biting. Aggressive biting is mainly reduced by socialisation (i.e. co-mingling) before weaning. Here, piglets learn to establish dominance relationships early in life which reduces fight duration when older. Tail biting, which is largely unrelated to aggression, is increased by early life undernutrition, social stress due to competition and cross-fostering. These factors are all influenced by litter size at birth. Familiar odours may contribute to reducing biting when pigs are moved from one environment to another by alleviating the level of stress associated with novelty. Tail and ear injuries pre-weaning may also occur due to mycotoxins from feed or straw, and can result in the affected piglet being bitten and the development of biters. Paying attention to tail and ear injuries pre-weaning is therefore recommended. Even though the barren environment of the pigs represents the major risk for expression of damaging behaviour, the pre-weaning environment should be optimized to reduce the likelihood of this problem. Foraging possibilities are essential for both laying hens and pigs. Providing pigs and poultry with the requirements for expressing natural behaviour and for reducing stress is therefore necessary to prevent damaging behaviour.