Young crows are fed mostly insects such as grubs, cutworms and other invertebrates such as earthworms. These are high in protein and will help them grow quickly. Like other birds that feed on rodents and other birds, Crows regurgitate pellets of fur and bones, although their pellets are not as solid or hold together as well as an owls. When feeding, crows post a guard who watches for predators. Usually it is an older experienced bird that can tell a harmless sound from a threatening one.
Several birds takes turns on watch so each bird has a chance to eat.
Because crows feed on other birds, they are often attacked or mobbed by smaller birds. You may have seen this when a flock of small birds dive bomb the crows as they fly over or sit on a branch of a tree. Usually the smaller birds are successful in driving off the crows because of their continued attacks and announcements to other birds that a predator is near. Some birds, such as cliff swallows, protect themselves from egg stealing birds like crows by nesting in colonies. That way there are many more eyes to watch and warn about predators.