Chickens are capable of flight, however their domestication doesn't require it of them. After hundreds of years of being cultivated by humans, chickens have evolved to be less competent at flying than other birds. Chickens are ground feeders, which means they eat grubs and small plants. Since they do not need to hunt down prey like a hawk, they also do not need the wing strength to fly like one. Chickens are able to fly enough to access trees when they need to escape from predators.