My very picky boy does great when I crush and sprinkle Instinct Raw Boost Mixers on his food. Just one little piece sprinkled over the whole dish of raw gets him to eat every last drop. I don't understand it, but I don't question it. I've also, in the past, sprinkled PureBites freeze dried chicken over his food. I know you said you've tried toppers, but have you tried either of those?If FortiFlora fails too, do you guys have any other suggestions?