All of my pets have been bloated since...forever ago. (I wouldn't complain, except I can't feed them Black Candy Bars or anything for the achievements. :P)

Is there anything on the site that actually decreases their hunger?

Nope, I guess you just have to wait 'till we fix this issue .-.

I got a pet out of the pound for the oofa achievement

maybe try that?

It's a glitch dear. programmers are aware of it, and I assume they're working on it.

Ah...thank you. I thought it was rather strange... Not entirely complaining, but... :D