What food do you recommend/anal gland issues

[MaryBethB.]

My dogs (9 and 10 year old shih tzus, in good health) eat Holistic Selects. It came highly recommended as did Wellness but they didn't care for that one. Well actually Raven will eat almost anything because she's a little piggy diva. All she wants in life is a good meal and a soft pillow. Cooper is much pickier. He eats his breakfast pretty well most days but needs to be coaxed into eating dinner. (a little gravy or broth or egg mixed in)

I have a few questions about feeding. Cooper has an anal gland issue more often than we would like. (We would like to smell that NEVER !) The groomer asked me if he'd been eating chicken. Could that cause it? He also had a kind of body odor smell on his hind end which the groomer though might have been from switching his food. We had changed from chicken to lamb but same company.

He's not constipated, and doesn't have diarrhea. He sees the vet and gets groomed regularly. Do I need to be expressing these myself. Please say no!!! And could his diet be contributing???

Is there a food that you would recommend that might be better?