Determinedly broody.

This hen has been broody for about a week and is beginning to lose weight and get really thirsty. It sits on nothing or unfertilised eggs. The two other hens can't get into the laying area and sit on top of their housemate to try and lay their eggs. Gone through various procedures for un-broodying her but she returns after around 15 minutes to the nesting area.
Given her water and food but reluctant to look after herself.
Maybe that's just what hens do.