Missing feathers

[LorraineIr]

Hi All, Can anyone tell me what might be happening. My lavender orpington rooster has lost the feathers under his chin and they've not grown back in. It's been several months. He and 7 girls are in a chainlink enclosure with bird netting above so no outside predators. My rhode island red flock is next door in a similar run that shares a fence line. They occasionally fight but can't really reach each other. We cleaned the neck with water and applied a spray for chickens. The girls occasionally pick at him which he allows for a few seconds. Does anyone have any experience with this? Any ideas/suggestions? Any help would be appreciated. This is my third year with chickens. I do not know the ages of the lavenders as they were gifted at full size. My reds are 1 except for a three year old from my original flock (we lost the other six over 6 months last year). thanks

 

[ChickenCanoe]

He may be rubbing them off on the top of the fence or something else.
The feathers likely won't grow back till after molt.