A mother bird feed their chicks

Birds feed their young by regurgitation. In this process, the parent bird eats and partially digests a protein-rich meal. Then the parent returns to the nest and brings the partly digested, soft food back out of its stomach and feeds it to the young in small amounts.
Allofeeding is a type of food sharing behaviour observed in cooperatively breeding species of birds. Allofeeding refers to a parent, sibling or unrelated adult bird feeding altricial hatchlings, which are dependent on parental care for their survival.