Sometimes when I wake my rats up(especially today) one or rarely two of their eyes are closed. They keep their eyes closed and I can tell by the way it's closed that they want to open their eyes, but for some reason they can't. I've looked at their eyes and there seems to be nothing wrong with...

Hey guys I’ve picked up some more new rats and the ‘Rex’ we were given has eyes that are almost closed, is it just a genetic mutation or is there something wrong?