A chick’s navel is susceptible to bacterial and fungal infections.

BY MOIRA K. MCGHEE

Even though a chick hatches from an egg instead of being born from its mother’s womb, it still has a “belly button.” However, the navel on a chick is more difficult to find, especially on a healthy newborn.

A poorly closed navel is a clear sign there’s something wrong with the chick and may indicate a problem in your incubator or incubation techniques. A chick’s navel is one of the most vulnerable places for bacterial and fungal infections, so it’s important to understand what a chick’s belly button tells you.

HOW IS IT FORMED

A belly button is basically a scar left behind from the umbilical cord. In unborn human babies, the umbilical cord connects the baby’s belly to the mother’s placenta to provide the blood supply the baby needs to survive. Because a chick develops inside an egg instead, the umbilical cord is attached to the yolk sac where it gets much needed nutrition. A few days before hatching, the chick absorbs the small intestine and the remaining yolk sac inside its body, leaving behind a navel at the entrance.

“From day 16 to day 19, the small intestine, or umbilical loop, retracts into the growing body wall,” says Eric Gingerich, doctor of veterinary medicine and technical poultry specialist with Diamond V, a global animal nutrition and health company. “Then, the yolk sac is drawn into the body cavity, which is directly connected to the small intestines through the yolk stalk. By day 20, the yolk sac should be completely inside the body and the navel should be fully closed by hatching. A ringlike muscle called the umbilicus becomes the future navel.”

Maurice Pitesky, doctor of veterinary medicine with the UC Davis School of Veterinary Medicine and Chickens Poultry Science columnist, adds that chicks “get their calories and nutrients from the yolk sac, which continues to serve as their main source of nutrition for the first two or three days of life.”