Got it! Okay, for some reason I didn't realize Grubbies was the brand! IT looks like a great feed, but the protein level is only 16%. You need a 20% protein feed at least. Is this the same feed? If not, can you provide a link?
https://grubblyfarms.com/products/g...lLkmW57W0QaVA5xf-JLOT2Cd2_GJt-bRoCMvQQAvD_BwE
If you don't have a 20% protein feed, it can result in feather picking for extra protein. Feathers are mostly made of protein, so that may be why they are picking her's. Do they eat the feathers, or just pick them?