AUSTRALIAN POULTRY FORUM™

I've got a puzzling one that I'm trying to nut out.

Will a chook reject a dud egg? Or what causes a chook to reject an egg?

Background - I had a Silkie sitting on 6 Plymouth eggs that were due to start hatching last Sun/Mon, they started hatching and I subsequently had another Silkie go broody so I put 6 Barnevelder eggs under her on the Mon. night. The 2 chooks were in adjacent nests with only a low divider between them. When I checked the first girl she had 5 hatched and was sitting on 1 more egg, the next day when I checked her I found she had vacated the nest, there was 1 egg in it and she had 5 chicks that I could see. I left the egg one more day and then thought I would inspect it to see if anything had developed at all, the egg was mostly filled with pale yolk and very little white. Today, 6 days after the first batch started hatching I discovered a dead Plymouth chick buried in the litter and the 2nd Silkie is only sitting on 5 eggs. I can only assume that I have disposed of a Barney egg and that I failed to notice any difference in the eggs but assumed the one in the nest was the same one I had seen earlier. But I'm curious why it was rejected and if anyone can tell me what the appearance of the contents means, if anything.

Hello, wickedwings,

You got the old noggin thinking...

Possibly a hen instinctively knows that a chick embryo does not continue to grow and thrive in the egg as there maybe a genetic or structural abnormality that occurred at the time of fertilisation. This can cause the new chick not to properly develop or die in the egg. I guess it could be similar to miscarriage and stillbirth and maybe it is just nature's way of not continuing with a life that would have resulted in a chick being hatched with major abnormalities

I'm suspicious about the hens sensing abnormalities given the number of posts on the forum concerning unhatched eggs, dead chicks in eggs etc... I wonder if they would discard one if the couldn't cover them properly?

I remember back when we had turkeys the hens would often kick out unfertile eggs. Generally this would happen in the first week or so. Often all you would find was the egg with the large end eaten out (large hole) no yolk. just a shell like it had been blown. I do rememer a few times finding the an egg still intact and putting it back under the hen, but only finding it kicked out the next morning. They would hatch every other egg. Nature has its way. Unfortunately some hens just are that smart and will sit on rotten eggs until they bust.

Rhode Red

Thanks Rhode Red, good to know.

Hi, wickedwings,

Our broody hen started out with several eggs last week, most of them hers and a couple of the other hen's as they were laying in the same nesting box when she got broody. Randomly she has discarded an egg out from her clutch the past week and this morning I found another one. So I wonder if there were some genetic defects present in her eggs as she and the rooster are related and the other hen non related, as a couple the remaining eggs belong to the other hen, I can tell by the shape and colour of them.

Don't know but I'm finding the whole thing interesting.

I do not know what tomorrow will bring as 2 of those remaining eggs belong to the other hen!

I have heard it said that some breeds know when an egg is infertile because of the weight when she turns them. It goes that at say 2 weeks the infertile eggs have not developed and therefore are lighter and some hens know this are discard the egg I have heard this said about a few breeds of birds also and not just chickens. I believe some parrots and cockatoos also do the same at a certain point of incubation when they know the egg or eggs are no good and throw them out or break them.

Ah I like that, some plausible reason behind the behaviour. Thanks Shine.