Posthatch

Posthatch refers to the period and processes that occur after an organism has hatched from its egg. In discussions of avian biology and poultry production, posthatch describes the early life stage of newly hatched chicks from the moment they emerge until they reach a more stable juvenile condition. The term can also be used more broadly for other oviparous animals, but its use is most common in poultry science.

In birds, the posthatch phase begins with the chick’s emergence and continues as it mobilizes nutrients from the residual yolk sac, begins exogenous feeding, and develops feathering, thermoregulation, and basic vitality. During this period the chick’s energy needs rise, while its digestive and immune systems mature. Proper nutrition, temperature, humidity, and lighting are critical, and early nutrition often includes a starter diet designed for rapid growth and disease resistance. The yolk sac typically provides nutrition for a short time after hatch, after which external feed becomes essential.

Management during the posthatch period emphasizes brooding conditions, sanitary facilities, vaccination schedules, and monitoring for posthatch mortality. Maintaining appropriate environmental conditions reduces stress and disease risk and supports uniform growth. Producers track metrics such as survival rates, growth performance, and feed conversion to evaluate posthatch outcomes. The duration of the posthatch period varies by species, breed, and production system, but it generally encompasses the first days to weeks after hatch, when chicks transition from hatchling dependence to independent feeding and growth.

Notes: The term is most often applied to poultry but can appear in discussions of other hatchlings. The specifics of posthatch care and timing reflect species, management goals, and local practices.