I have a broody right now who has been sitting on eggs for a week. She is sweet and friendly too, and when I open the nest box to check on her, she puffs up real big and makes a coo sort of noise at me. She leaves the nest box for a little while every day to poop, eat, drink and dust bathe. All the while she makes bock-bock noises and attacks everybody else to remind them she's still top bird. I knew she was dedicated when she refused to sleep anywhere but the nest box at night and when she started telling off the rooster. She would drop a wing and puff up as big as she could. You could almost hear her saying, "Don't touch me - I will end you!"
If your hen is doing these things, she may be broody.