My broody hens have the same kinds of behaviors:
- They tend to make this weird sort of throaty cluck, almost sounds like they're gulping.
- They'll often pull their belly feathers out to warm the eggs better.
- They'll lay claim to a nesting box and won't want to leave it. They'll only leave once or twice a day to feed, drink, and leave a HUGE poop somewhere.
- While nesting, they'll tend to spread their feathers and bodies out to cover a whole clutch of eggs. They're much more likely to peck you and they'll make this weird growling noise when you approach the nesting box. Some people call this "the angry pancake."
- Broody hens tend to be ornery when they are out and about, and will growl and be otherwise aggressive to the other flock members. I had one last summer that would have all her feathers extended when she stalked the feeders on her daily walk, looking like a feathered puffer-fish.