Q- Why would hens open their eggs? I read that hens may open eggs they are sitting on for hatching before the due time. Why would they do this?Ellen Cooper, via email
A – VR says: A broody hen has wonderful instinct. She may discard an infertile egg and she will know this because after she has got off the nest to eat, drink and defecate, she will feel with her sensitive breast skin that an infertile egg will be much cooler than a fertile egg – no living embryo inside it. Hens do not usually try and open an egg before the due hatch date – why would she? The broody instinct means that she stays in a sort of warm daze for about 18 days until she hears cheeping, then the broody instinct becomes the much more defensive and fiercer maternal instinct against presumed predators, not against the chicks! If you try and help a chick out it is likely to be a disaster since, if they cannot hatch on their own, there may be something wrong with them. If you are artificially incubating eggs, remember not to put water in the incubator until the eggs pip, and make sure that the bulb of the thermometer or the digital probe is just above the eggs so that the required temperature is maintained.
Slow-hatching eggs can be old eggs, temperature too low or too much humidity early in the incubation.
Incidentally, if you do not want a hen to be broody, putting her in the ‘sin bin’ only works if she is left in there for about a fortnight – a few days is not enough for her hormones to re-set themselves.
DOES YOUR POULTRY HAVE A HEALTH PROBLEM?
If so, you can email Victoria Roberts BVSc MRCVS: firstname.lastname@example.org or
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Exeter Airport Business Park, Exeter, Devon EX5 2UL
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