As long as they have plenty of room they should heal well. Gentian violet, an antiseptic, anti-fungal medicine can be used to color the red areas dark blue to keep them from pecking each other. Pine tar can also be used for that. Good luck with your chickens.
If you are not able to get a commercial balanced chicken feed, you can mix grains such as corn, wheat, barley, sorghum, oats, animal or fish protein, and add vitamin b complex and calcium to balance out the diet. Grinding feed together can help to prevent picking out the tastiest bits. Here is some reading about poultry feed around the world, and recipes:
http://www.poultryhub.org/nutrition/feed-ingredients/
https://www.thespruce.com/make-chicken-or-poultry-feed-3016558