What term is used to describe chicks that are fully developed at birth?

The correct term for chicks that are fully developed at birth is "precocial." Precocial chicks are able to walk, run, swim, and feed themselves shortly after hatching. They are typically equipped with down feathers and have their eyes open, allowing them greater mobility and independence. This adaptation is particularly beneficial for species that nest in open areas, where survival depends on the chicks' ability to evade predators quickly.

In contrast, altricial chicks, which are not fully developed at birth, rely on parental care for feeding and protection until they mature enough to leave the nest. Nestlings specifically refer to young birds that are still in the nesting phase but may not yet have the capabilities associated with precocial chicks. Fledglings are birds that have just acquired their feathers and are learning to fly but are not synonymous with the state of being fully developed at birth. Understanding these distinctions helps clarify why "precocial" is the appropriate term for fully developed chicks at birth.