I know what it sounds like but it's certainly not a pregnancy, the mouse in question is my little boy Pecan who I had neutered just after he impregnated my little girl Cashew. So i know for a fact he is a boy.
But the very worry thing is tonight he looks pregnant, distended from his chest downwards like he's swallowed a golf ball. And it's soft to the touch, he doesn't seem to mind me poking him about either but he has always been the kindest and sweetest temper of any mouse I've had. So it's hard to say if it could be sore for him.
Other than the fact he looks ridiculously swollen, he is acting perfectly normal, eating the treats I offer him and coming out for food at dinner time.
I am very worried though, what could this be?