she may have been molting in new feathers and she was letting him pick at the blood feathers
or
here is the kicker
she is NOT HIS favorite hen
that roosters will do and you may not ever get her put back with him
so doctor the hen and hope for the best
Hang a head of cabbage wrapped in a piece of chicken wire about 12- 18 inches from the floor for large fowl One can hang a piece of baled alfalfa hay wrapped in a piece of chicken wire also from the ceiling. Restocking a new piece when they have eaten the leaves out.
NATURAL PROBIOTIC
Also another thing for good health is the using of buttermilk and, crumbles , and yoguart.
Soak 1/2 gallon of crumbles and 1 gallon of buttermilk or sweet or soar milk and 1/2 pint of yoguart. In a plastic pail mix and stir good in the morning and if dry add more milk. adult chickens 3-4 tbsp .
By making the wet probiotic mash they waste less yoguart and get it into their gut.
Besure and clean and dry the plastic or wooden feeders after they eat all of the wet mash ( generally what they can eat in 30-40 minutes.. I would only make what I needed for the
amount of birds I had. Feed so each adult bird can have 3 tbsp per feeding.
Feed this once a week. Besure and feed 16%(or higher) protein crumbles to the hens
so that with the oats the protein content isn't deminished.
for the oat mixture just have a feeder of whole horse oats and ofcourse granite grit
so that they can peck away in the oats.
This should give them something to do besides eat feathers