Are they perhaps very dehydrated? Check their water bottles to make sure that they are working properly.
Other than that, it is possible they have a parasite, try treating them with iver-on (or another treatment if you have something).
I have had mice with a working water bottle, just not be able to push the ball in properly to get the water. (though another cage of mice could) so deffinately check their water bottles. Another good way to tell if they're dehydrated is to pinch their skin. If it does not snap back into place, they are likely dehydrated. Also, if they lick your hand if there is water on it, they are probably dehydrated.
Other than that, it is possible they have a parasite, try treating them with iver-on (or another treatment if you have something).
I have had mice with a working water bottle, just not be able to push the ball in properly to get the water. (though another cage of mice could) so deffinately check their water bottles. Another good way to tell if they're dehydrated is to pinch their skin. If it does not snap back into place, they are likely dehydrated. Also, if they lick your hand if there is water on it, they are probably dehydrated.