ABSTRACT
The group size in which livestock are kept can also have effects on their health. Some of these reasons are those discussed earlier, relating to pathogen exposure. Other effects on health are due to stress from group competition. Anytime animals are grouped, they will compete for any resource that is limited. In production agriculture, all animals being fed to produce meat or milk are not being limited in feed or water, but limitations can occur due to limited access. Limited access to the feeder or water will cause increased aggression, which, in turn, will activate the stress response. Broiler breeders and sows are limitfed, and thus a high degree of aggression can be seen when they are housed in groups. Those animals lying intermediate in the dominance hierarchy tend to be more stressed than either those at the top or bottom.
