Feather growth needs protein. Your 18% protein feed is good, but it is a general diet protein. If you wanted to boost their feather recovery, EXTRA protein would help recovery sooner. :thumbsup
I would suggest you increase the amount of protein in their diet. You can add some catfood, (canned, or dry). Leftover meat from your meals. Sardines. Just add small amounts, so they don't have too high of a dose. A too big of a dose would possibly cause runnier stools, and somewhat...
Can you post some pictures of the current condition of your hens?? Maybe others readers can identify problem, and offer solution??
WISHING YOU BEST,,,,,,,,,,,,,,,,,,,,,,,,, :highfive: