Baby animals are often born in groups, and while "litter" is a common term for many mammals, other words describe the babies of specific animals and birds.
A litter is the number of baby animals born to one mother at the same time. You can talk about a litter of puppies, kittens, hogs, raccoons, squirrels and many other mammals. However, the award for most possible terms for a group of young mammals has to go to cats -- a litter of kittens can be called a kindle or an intrigue.
Young birds born at the same time are often referred to as a brood. Human children in the same family can be referred to as a brood, although they're not usually born in litters.
While baby chicks can be called a brood, so can a group of adult hens. But baby chickens also have two other possible terms, giving them the award for most possible names for a group of young birds. A brood of baby chicks can be called a clutch, and a clutch of baby chicks can be called a peep.
A group of alligator hatchlings is called a pod even though, unlike peas, they're not contained in anything. Pod also refers to groups of adult water mammals such as dolphins, whales, seals and walruses.