It may seem odd but in nature many animals will eat their own kind, even hens will sometimes eat the egg that they just laid.
If it makes you feel better, any egg that goes back to my chickens has been cooked and is no longer an egg that they would recognize.
I do not feed any chicken meat back to the hens but they do sometimes get a left-over ham or steak bone. That is rare though.
Remember that chickens are omnivores, they eat meat and vegetation. They will happily eat frogs, mice, toads, insects and darn near anything else that they can swallow.
And as someone said, if you fall down in your run those chickens will eat you too.