We all hope for chicks that are healthy, happy, and hatch with no birth defects, unfortunately, this isn’t the case for all chicks. Some chicks will hatch with the yolk sac outside of their bodies.
If this is happening to you, and you need answers as to why this is happening, and what to do, then read on
If your bird hatches with the yolk sac attached you may need to leave it to dry, or cut it off depending on the condition of the chick and yolk sac.
Chick hatched with yolk sac attached
Chicks may come out of the egg a little wet and cold, but they should ideally hatch with nothing attached to them. If the bird hatches with the yolk sac attached to it, then this means that the yolk sac has not been absorbed into the body in time.
This isn’t ideal, but it can be managed and the bird can do just fine if managed correctly.
Why chicks hatch with the yolk sac attached:
Hatching too early: A chick in the egg will absorb its yolk sac just before it hatches, this usually happens on day 16-20.
If your bird hatches too early, before it’s given a chance to absorb the yolk sac, then the bird will hatch with the yolk sac on the outside of its body but still attached.
Incorrect incubator temperature: A chicken will usually, hatch too early if the temperature of the incubator is too high. Temperatures above 99.5 degrees Fahrenheit (37.5 degrees Celsius) will cause birds to hatch around 24 hours earlier than usual.
Assisted hatching: A chick hatching with its yolk on the outside of its body can also happen as a result of assisted hatching. This happens if you try to assist the bird to hatch but do this too early.
If the inside of the egg is still wet when you assist with the hatching, then the chick will hatch with the yolk sac attached and on the outside of its body.
What to do:
If your bird hatches with this defect, most will advise that you leave the bird alone and allow it to absorb the yolk on its own, or, leave the bird alone and allow the yolk to dry out and fall off,
The yolk should fall off within a couple of hours. Feed the bird food and water during this time and after the yolk falls off.
You may also want to apply some Neosporin, a triple antibiotic ointment, or iodine on the yolk sac to keep the area from developing an infection and help it to dry off.
With that being said, this is good advice but results may vary. Not all chicks will be so lucky:
If your other chicks are curious, chicks usually are, then the other birds may instinctively peck at the yolk sac if the bird with the birth defect is not isolated. This pecking will eventually kill your bird and this will be a very slow death.
If your bird is isolated, but accidentally steps on its yolk sac, then it can give itself a hernia and die. The yolk sac may also pull out some of the bird’s innards if it begins to slide out
The yolk sac, which should ideally already be in the bird’s body, can also develop an infection if left out. If any of this is happening, You can intervene by cutting the yolk sac off.
Cutting the yolk sac off will prevent injury to the yolk sac in the future. If you choose to do this, be sure to clamp the stump for 30 minutes or cauterize the stump immediately after cutting.
Dipping the bird’s bill in sugar water will keep it going after you’ve removed the sac.
What you choose to do will depend on how the chick and the yolk sac are doing. If the sac has absorbed into the chicken’s body then you won’t have to cut it off but if the sac is making life worse for the bird you may have to bite the bullet and cut it off.
The function of the yolk sac in chickens
Chickens develop inside eggs rather than in their mother’s womb like mammals do, however, these little birds are also attached to an umbilical cord just as mammals are. Their umbilical cord is what attaches their bodies to the yolk sac which is a source of nutrition.
The yolk sac stores enough calories and nutrition for the bird to live off of for the first two to three days of life, this is why these birds can live without food for the first few days.
The yolk sac is also where birds get their antibodies from, if the yolk sac doesn’t fully absorb before or after hatching, then the bird may not grow to its full potential.
In conclusion, as much as we’d hope for our birds to come out with no issues, a prematurely hatched bird can hatch with its yolk sac outside of its body.
You can choose to let the bird absorb the yolk sac, but if the yolk sac hasn’t absorbed after a couple of hours, and it is being stepped on, pecked at, is growing an infection, is moving out of the bird’s body (and taking some of the bird’s innards with it) then you should remove it
If you enjoyed this article then you may also be interested in other chicken related articles. Here are some articles that you may be interested in: Chick Hatched With Something Attached, Chick Hatched Too Early, Egg Pipped But No Movement