Broody Hen why didn't eggs hatch? (Perfectly formed inside egg)

[Trmacc]

Hi, had a broody hen, she was sitting on about 14 eggs, she threw 4 out over time. No sign of any chicks so eventually at day 30 I took her off the eggs. Have opened the eggs and they contain what looks like perfectly formed chicks. The membrane was quite wet (not shrink wrapped) no sign of pipping or anything. She has been sitting fairly tight on the eggs, only left them for 10 mins every 5 or 6 days and was in a quiet cool place away from rest of flock. Any ideas?

 

[Perris]

This is described as 'dead in shell', abbreviated DIS. There are multiple possible causes, not all of them perfectly understood. Sometimes the chick drowns or suffocates (they should not be turned during the last 3 days to avoid inadvertently causing this); sometimes it lacks the energy to break through (especially if the shells are very hard); sometimes they overheat or get chilled; sometimes something else went wrong. 14 is quite a lot for a hen to try to cover and keep them at the right temperature and humidity. Was it her first time, or was she an experienced broody?

 

[Ridgerunner]

I'll include a couple of links that might help you figure out what could have happened. This is written more for commercial operations but a lot of it can apply to us.

Trouble Shooting Failures with Egg Incubation | Mississippi State University Extension Service (msstate.edu)

Common Incubation Problems: Causes and Remedies (ucanr.edu)

I find it unusual that they were all like that. If a hen has trouble covering all the eggs one can get pushed out, cool off and die, then gets moved back under her. Another egg gets pushed out and dies. This means some die before all the chicks are fully developed. And usually you do not get good hatches. If most of the chicks were fully formed this just does not sound right.

Hens and eggs come in different sizes. A tiny bantam might have trouble covering four regular sized eggs. I typically give my hens 12 eggs they size they lay. One time a hen had trouble covering that many so I gave her 10. I've given one hen as many as 15 and she had a great hatch. One time I had a hen hide a nest and bring off 18 chicks. I never found her nest so I don't know how many eggs she had.

I do not have a good explanation for what might have happened, especially with a broody hen. In an incubator, maybe, but not with a hen.

 

[Trmacc]

I know, never experienced it with a hen as opposed to incubator. First time broody, she is quite young, maybe a year. She is a good sized hen, I did think 14 was too many but she quite quickly pushed out 4 (weirdly the 4 eggs that weren't hers, brown ones and she's a blue layer) so was sitting on 10 and seemed to be covering them well She was fussing round the eggs quite a lot so maybe she kept moving them when she shouldn't. Shells were not overly hard and membrane not overly tough so I've eliminated what I see as the usual problems. Just very weird and disappointing.