Incubation - what went wrong ?

Today I took the decision to turn the incubator off. Although a very strong healthy chick hatched yesterday I decided that we would cut our losses with any remaining.
I did candle and listen to the unhatched ones first, also floated them in warm water - no reaction. On breaking them open one Welsummer was starting to go bad, the other two did have almost, if not fully grown chicks in them. Don't think they were alive, but even if they were and hatched in a couple of days, they would be a week behind the others. The Sussex I didn't even bother breaking.


So conclusion.....The Speckled Sussex I think more than likely were a poor set of eggs. Either poor parent stock or poor storage of eggs before incubating.


The only other possibility and one I am going to check out before the next setting is temperature variation. It is a fan assisted incubator so there shouldn't be.

In the incubator I have the mercury thermometer, that came with the incubator, it is set in the center and should be level with the center of the eggs and read 100F. I also have a digital hygro thermometer.
These two never read the same. My husband recommended trusting the mercury one, so we went with that.

The digital thermometer I placed in the corner of the incubator away from the rolling floor, here it always read lower than the other.When I candled the eggs I moved the digital one close to the mercury one and the reading did go up.


So now the incubator is empty and cleaned I am going to run it for a few days with the digital thermometer in various places to see if there is any variation in temperature.


Hot and cold spots would explain the uneven hatching times.The first pipped on Friday, hatched Saturday.The majority hatched over the weekend (21 days).We also had one chick on Monday and one yesterday, with two more that may have possibily hatched in a day or two.



I can't remember where the eggs that hatched first were palced in the incubator, also when I candled them I know I moved them around, so I knew which I had candled and which I hadn't. As well as testing the temperature of the incubator empty, next time I shall take note of where the eggs were and when they hatched.