I am working on in vivo project and recently faced with an odd problem. I have 3 groups of female BALB/c mice (2 groups of 10 and 1 group of 2). The problem is with two -mice group that eat a lot of food in comparison to the other groups!! I have to feed them every other days with loads of foods! I have had lots of mice during previous projects and never seen such mice! I am afraid if something is wrong with them. Please help me.