Yes, chickens are stupid. They'll let you catch them and chop their head off.
Not really. It's kinda like herding cats. The best way to do it is go into their coop in the morning before you open the door and pluck them off their perch.
As for hatch rates, I still haven't figured a winning formula. Hens do the best job but they will reject sick or unhealthy chicks (even when they seem perfectly healthy to us). I've tried bringing these chicks in and raising them with other chicks but they rarely survive.
Broodiness is an extremely strong instinct. Hens will set for months with very little food or water. Sometimes one poor hen will set on eggs forever and then right before the chicks hatch another hen will decide to sit with her. If the interloper is a dominate hen, she ends up being the adobtive mother. Other times the two will raise them together. Often one of my hens will run off and set on eggs in the brush. I'll think she died or something and next thing I know she'll emerge with chicks in tow. Last year I had a sex link that did that and they're bred to NOT get broody. Go figure.
Just like any other bird, they'll seek a safe place for their chicks. A tree seems a logical choice for any bird. Some just seem to prefer sleeping in trees. They are still birds, after all. Generally they get picked off one or two at a time but I'm not going to climb a tree to get them. Sometimes I've been able to retrain them to go in the coop but some you just have to let go.
Chickens aren't the most intelligent creatures on the earth, but some are smarter than others. I have a couple of Speckled Sussex hens, Hattie and Jenny Any Dot that come running when I come out and will crouch down to be picked up and will follow me around carrying on the chicken version of a conversation. They also manage to get humans to turn over bricks and rocks so they can grab the worms hiding underneath.
Cindie