Quote Originally Posted by zimbabwepegasus
If there are two beardies in the same cage, one could be hogging the basking spot and UVB. If you are noticing a marked size difference, this is probably the problem and you will need to separate them, or at the VERY least set up two basking spots. It is a dominance sign though, so watch very carefully!
I had a female with that problem when i bought her. The male she was with was taking the food and she became quite skinny.

I didn't even think about that possibility. I'd definitely give them the second basking site and maybe seperate feeding (taking the other out).