I have had two hens go broody this Spring. I put each one in a large dog kennel right from the first. I put food and water in the kennel but I don't think she ate or drank anything the whole 22 days. She hatched all seven eggs. After 3 days, I put her back in the main yard and put a light in the kennel to keep the babies warm. They are 3 weeks old now. The hen was skin & bones but started back eating and drinking as soon as I put chick starter in the kennel. Back in the yard, she is still clucking some but doing fine and regaining her weight.
The second little hen just started, day 4 now. She too has not been off the nest to ear. I didn't know they could go 22 days without food or water but they can. They seem to minimize energy by being perfectly still. They will “growl” and fluff their feathers and peck at you when you get close to them but that is all.
This is my second try at letting them hatch their eggs. So far, 100% hatch rate. However, my first hatch, a rooster, decided he didn't like the others chasing him when I put him with the flock, and I forgot to clip his wings, so he flew over the fence into my neighbors yard and was quickly caught by their bird dog! Seems the hardest part is introducing the young ones back into the main flock. I have 3 Guineas that run with the chickens and they are mean to the young ones as well as one of my prized little bantam roosters. He has no tail feathers at all. The Guineas pulled them all out.