Cotton has a lot of food allergies or intolerances. I've never known if they bother him, but he gets goobie, gross eyes. I always thought the problems were with proteins like beef, pork or poultry. Quite a while back, I switched him over from a mid-level dog food to a premium level and saw a huge difference. The truth is, I never knew if the change was because of the better quality food, the decrease in preservatives, or the protein source of the foods. What I do know is that once he started eating this premium food (bison or fish based) and cut out meat-based or preservative laden treats, his eyes cleared up.
About a year ago, I introduced freeze dried chicken to his diet. He loves it, and it does a great job at cleaning his teeth. Unfortunately, his eyes don't agree. They've been goobie and gross ever since, but I thought he didn't notice. I figured that the dirty eyes were worth the trade off for a treat that he loved and clean teeth.
After the scare with the chicken jerky, I stopped giving him any form of chicken. I just couldn't take the chance. Instead, I've been making what I call "chips", which are dehydrated slices of sweet potato, for about a month. His eyes are clearing up. More importantly, he seems way healthier.
Where as last year, he seemed stiff and sore after long walks and often had to be carried home, lately he has been down right peppy. He leads the way, all the way home and shows no sign of discomfort. Short little bursts of energy used to occasionally cause him to rip around the living room for a lap or two. Now he's acting like he's manic. He runs around the house all the time. He eggs the poodle into playing chase a few times a day - and the games will go on 10-15 minutes if I let them.
I don't know what else has changed, other than the removal of chicken from his diet. Whatever it is, I'm glad he's feeling so good. On the other hand, though, I hate the thought that I've been feeding him something for over a year that, in comparison, was making him feel downright crappy.