Many people who don’t understand why eggs can never be an ethical foodstuff for humans are surprised to learn that selective breeding for egg laying has made modern hens prone to cancer and other reproductive diseases. As such, medical researchers are using hens as models for studies into ovarian cancer in humans.:
The domestic laying chicken has been intensely selected to be a persistent ovulator. That is, the tendency for broodiness has been nearly eliminated and, given the appropriate lighting and nutrition, many strains of laying hens produce an egg on almost every day. […] Commercial laying hens also spontaneously develop ovarian cancer at a high rate, and susceptibility to this disease has been associated with ovulatory events in women.
Think about all that for a second.
Hens are forced by genetic manipulation to lay eggs so frequently that they are highly predisposed to reproductive cancers. The thing they were bred to do for humans will likely kill them.
Of course, hens die from lots of other things, too, as their reproductive system breaks down; this is why most hens do not live beyond 4-5 years…which is also the age they mostly stop laying. Those chickenly problems aren’t quite as useful for humans, apparently…
Equally awful, as the Poultry Science abstract cited above also makes clear, humans have bred OUT the mothering instinct in most hens because it interfered with egg laying.
Put another way, hens don’t even get the chance to experience motherhood…because nothing in their hijacked biology compels them to.
Every time someone eats an egg, these are the things that are being supported and normalized.
That’s part of why eggs don’t “just happen,” and why laying hens can never be truly “happy” when you steal the object of their suffering.