If it doesn't smell rotten, this would be a good time to remove it. Add some warm water over the egg it should loosen it. Use a eyedropper if you have one.
One was born with twisted toes and the other one couldn't stand or walk with droopy head. Those 2 were late hatchers. First time culling chicks it was very easy to do.
Also I already have one disabled roo that I'm studying.