I had a friend whose hens were always bare on various parts of their body. I never did figure out the cause of that. They had a normal layer diet, so should have had enough protein for good feather growth, & only 1 rooster for lots of hens. The hens did seem unhappy, frightened & quarrelsome, so they may have been pulling each others' feathers?? However, the bare patches seemed pretty uniform on both side of their bodies, & I'm thinking they'd be more random if they were from plucking??
With you only having two hens & plenty of space, it would seem not very likely one hen would attack another that much. Have you seen the one hen act really rough toward the other regularly?
All that said, I only have two hens & when a few months ago they started laying after a long period of infertility from illness, their hormones started raging like crazy. They fought over who was supposed to be my rooster's favorite hen.
They are Ameraucanas, & the hens pulled each others muffs & beards out. But the problem was very easy to identify--You could see & hear them fighting.
(They did settle down after a few days, especially as the illness took back over their reproductive systems & they stopped laying.)
