help :(

[Cerra Haybecker]

hi i got home today from school and one of my babies had his body
completely contorted (?) and he was cleaning his bum area like mad he
looks like he is dislocating his hips when he walks i took him out of
the cage and he walked fine
the cage smells kid of bad but none of the other gerbs seems sick?
is this tyzer's diarehea or something else
im quite scared and he still seems strong
please help me
thanks
c.