unhatched but fully developed

[Casey207908]

I had 9 eggs which i candled on day 18 and they all looked good. 6 of the 9 hatched within a 24 hour period on day 20-21. I left the remaining 3 in the incubator until Day 25 hoping they would hatch but with no sign of life I cracked them open. All 3 had fully developed chickens with feathers and all. They looked like they should have hatched, no deformities or anything. Can anyone tell me what could have gone wrong and why they wouldn't have hatched?

 

[sumi]

There are a few possible causes for chicks failing to hatch at this late stage, in a nutshell they are:

- Inadequate turning, especially during the first 14 days of incubation
- Humidity too high during incubation and/or lockdown
- Incubation temperature too low and/or lockdown temperature too high
- Eggs got too cold at some stage during incubation or lockdown
- Nutritional deficiencies in breeders
- Hereditary
- Breeder disease
- Inadequate ventilation during incubation or lockdown
- The eggs were stored too long or incorrectly before incubation.

Hope that helps!