Genetics and the Behavior of Domestic Animals

Over-selection for production traits has caused animal welfare problems such as feather pecking in hens, tail biting in pigs, and overly aggressive animals. In dogs, over-selection for appearance traits has caused neurological problems such as deafness. Both feather pecking and tail biting may be displaced foraging behaviors, because these behaviors are reduced by providing foraging materials such as straw. Another problem is hunger in broiler breeder hens and breeding sows. Animals that have been selected for rapid growth are also selected for a huge appetite. If breeder animals eat to satiation, they will become obese and have health problems. High-roughage feeds may improve welfare. Researchers suggest that new genetic breeding tools could be used to select against harmful behaviors and still have a productive animal. Breeders must avoid creating animals that will have poor welfare even when they are housed in the best environment.