Have you ever been around a farm?
Something I’ve learned about chickens is that there is a definite "pecking order" to the flock. Within the flock of hens, one of them always becomes dominant. She will peck away at any hen that makes her angry or gets in her way. At first, the other hens that get pecked don’t like it and try to retaliate. But when they see they can’t win, they begin to turn on each other.
Each chicken that isn’t the dominant one begins to take our her frustrations on the others. And soon there became a pecking order. The next strongest would picks on the next weakest, and so on and so on. Until one hen is left who is the lowliest and weakest in the pecking order. And she has no one to peck at, so she’ll just run away from all the conflict.