Chickens are cannibalistic. They also wake up when the sun comes up, go to bed when the sun comes down, and have all their food preferences according to what's healthy for them.
If a chicken eats its one of its own flock who is sickly or has an open wound, it's because it's good for the chicken to do so. And furthermore eating one's own type ought to be beneficial since all the same building materials are present in the exact same ratios.
We humans could learn a thing or two from nature.
Edit: there are no gay roosters though even though all roosters are cannibals
Chickens have been eating each-others for million of years since the dinosaurs from where they evolved, also they aren't mammals.
Cannibalism between humans will end up making you very sick.
Mammary glands were a mistake.
You mean on an evolutionary scale?
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