I have a litter of feral kittens I'm taming to adopt out. They are doing well but a few of them have big round bellies, despite several rounds of deworming (Strongid, Revolution, Drontal). While it's certainly possible they just have really bad cases of worms from being outside, could this be anything else that can be treated? They are very healthy otherwise, pooping well, etc. All have tested neg for FIV/Felv. I don't think it's anything besides gas bloating, but I'm not sure what to do to help.