My chickens had started their lives with me with daily access to an open-top chicken run. Then they decided to free range themselves.
Free range was OK for a while. They happily turned my yard into a shredded wasteland of unpalatable weeds and chicken poo. When hawks started visiting I covered their pen with bird netting, but still let them free range every few days.
Then nature caught up with us. A hawk killed two of the hens. So I stopped the free range activity and kept them penned up all the time. This caused some chickeny frustration, though they did eventually adapt, leading to a lot of fertilized eggs.
Recently I let them spend some time in a tractor. They were cooperative for a couple visits. Then they decided they would rather free range. Oh the chickeny joy! For three full minutes they paraded around their old run , squawking and scratching and pecking and gobbling up weeds and seeds and bugs and leaves and invisible bits of deliciousness. I saw no hawks, so I decided to roll with it.
Just as suddenly they decided they did not want to free range at all. They raced to the pen in the most dignified manner possible, like a bunch of chubby mall-walkers in spandex. Dumbfounded, I stared at them. They looked at me. Then they looked at each other. Then they looked at me again.
Casting about, I spied the terrible threat that made them run for safety. It was a single rabbit, complete with twitching nose and chewing on a bit of grass.
I tried to explain it was not the Easter Bunny, but they were having none of it and guarded their eggs with zealous pacing and stink eyes.