I agree with Scott, that it may not be too unusual right now. Are they molting pretty heavily? Also, if you have just changed their environment, this could be a result. Other questions I would ask you are:
Do they have plenty of space?
Do you have cocks and hens all together?
Are they penned with any other birds?
A new environment could cause some stress. If they do not have adequate space and are competing or courting heavily, they will loose weight. Just a few things to think about!
Good luck and I will see your name on the membership list soon!