Hard to tell I know
Especially as they all have the same waistline. Maizee must've had to "go" really bad to risk being in the stall with Pippin. He's been known to give chase just because! Plus, the minions still have the occasional skirmish. Even a fat cat could be flattened easily. Luckily they both were hunkered down over feed bowls, Merlin had just noticed her. He'd have merely snorkeled her bum though.