comments:
I bet their internal parasite load is too high. They have been on the same ground for 5 years probably? You need to treat them for parasites. Aquasol is not recommended during periods of feather growth or they will regrow funny. I use ivermectin 2x a year for this problem. Poultry DVM is a great resource. For 16 chickens I recommend getting a 16 syringes and pre filling them with .2ml of the cattle drench from your local feed store. https://a.co/d/0irZV2DK Go in at night and apply it on the back of their neck right above their wings. Make sure you're not squirting it on just their feathers. Retreat after 10 days. Add more substrate in their run (I recommend a heavy amount of mulch.) Fyi- Diatomaceous earth works by being sharp and cutting parasites. When they eat it and it gets wet it does not do anything internally because it softens. It only works when it's dry. Unfortunately chili isn't a proven method to deal with parasites. I do use it but it's not gonna do anything medically significant.