I'm guessing I've tried every kind of tiny canned food produced. The first time we almost lost him to, well, self starvation, my vet had me try meat baby food. He ate it for awhile then scoffed at it. Pretty expensive stuff too for the amount you get.
He will literally go for days without eating, causing his blood sugar to drop drastically. Rotisserie chicken seems to be the only constant thing he eats.
I've been asked more than once for my Chicken chili recipe when people see Chili chicken on my shopping list.

Seriously, I've been concerned he is not getting the right nutrition for the past 5 years from eating only chicken. Which is why I was happy to see him eat big bub's food. He will be 14 next week, has a heart murmur rated 5 on a scale up to 6, has a collapsed trachea, and goes into serious wheezing fits. My vet says, "Let him eat chicken."
Thanks for the info on Costco food however. I'm taking Soph and Syrus off it immediately even if it's only a couple of tablespoons.

Their regular food is grain free.