If you are feeding raw, chicken and green tripe isn’t a balanced diet. They need the correct ratio of bone, muscle meats, organs, bone. And I wouldn’t leave raw out for him to free feed.
Get a ratio together that is correct, and pre-make meals. Flash freeze on a cookie sheet, then put into individual bags or containers so you can pull out one meal at a time. I give my dogs (not on raw) 20 minutes, if they haven’t touched it in those 20 minutes, bowls get pulled until the next meal, and I do not increase the portion size if they skipped their morning meal. It doesn’t take long for them to catch on.
If he pesters you for food, ignore him. He has 20 minutes (or however long it takes to breakdown a raw meal, no experience on that end) and pull the dish. Same with the evening meal.
If he loses a lb or two, it’s worth it if you can get him onto a schedule where he knows once the bowl is pulled, no matter how much pestering he does, he will not get food until the next meal time.
My GSD/Husky goes on food strikes. I offer at every meal, and if he doesn’t want it, I pull it. He’s never gone more than 2 days before he gives in. It’s also a sign that he’s grown bored with the taste of the same kibble, so I switch to a different food in the Fromm family. No need for my guys to switch slowly, they can go from one combo to another without digestive issues that come by switching brands. Fromm has plenty of grain in products to choose from.
If he is not eating, and showing sudden behavior changes, I’d get him to a vet ASAP. Sounds more to me like he had a medical issue going on than just being a picky eater.