We rescued a feral young cat, now named Calle, a few months ago. Initially, she was so skinny that she ate whatever the adoption agency provided us. We quickly transitioned her to Weruva canned and continued to give her dry kibble provided to us in an unmarked bag by the agency as treats. After a month or two, we noticed she was scratching her neck, which became bloody. Because she was feral, she was still a bit skittish with us, but we could feel bumps all over her neck and took her to the vet who said she either had a food allergy or flea dermatitis and recommended treating her for both. She is now on Hills Z/D diet, which surprisingly is still chicken-based. 

(As a side note, we have two other cats;  one had/has a food allergy and we learned about a year ago that protein allergies are not uncommon. This cat is on Orijen six fish and is doing well.) 

Back to Callie … she is not scratching to the extent she used to and she is not bleeding, but she still has bumps on her neck. It is now almost two months since she’s been on her new diet. I don’t know if she still has remnants of her food allergy or flea dermatitis or if the food we are giving her is the best we can provide. I’m reading that in addition to protein allergies being somewhat common amongst cats, the Hills ZD diet has changed, and that many people (and cats!) are unhappy with it. We have three cats and each one of them has a separate diet: one is diabetic, the other has a food allergy and is on Orijen fish, and Callie is on ZD. Any recommendations for improving Callie‘s diet and maybe even slowly transitioning our Orijen cat onto this diet as well?

Thanks, Reddit community. 

Possible Protein Allergy Cat Food Recommendation Needed