Baby chicks dying after hatching

[Melcam]

We have a broody hen and decided to get some hatching eggs for her. It is now day 21 and momma is still sitting on her eggs. We checked today and there were two dead hatched chicks and the rest of the eggs are intact. She is in her own brooder so there is no way other chickens could have gotten to them. Not sure what, if anything we should do….
Any advice would be appreciated

 

[azygous]

A mystery requires investigation and surveillance.

First, did you look over the dead chicks for wounds? It could be the hen is killing them or rats. There likely would be signs of injury.

By "intact", do you mean the chicks in the unhatched eggs are alive?

What was your source for the eggs? It's possible there is an avian virus involved that is passed to embryo in the egg by an infected hen. If there are no signs of injury to the two dead chicks, this could be a possible cause of death, and it would also cause high mortality in eggs that do not hatch.

This is where an animal cam would be a big help. You do need to observe the hen's behavior with hatched chicks.