Hamsters...

I could write about all sorts of thing right now but I'm actually quite worried about one of the hamsters.  He been drinking an awful lot the past couple of days and when I went to stroke him I saw that all the fur from the underside of his neck and front legs has gone.  He's a very old hamster but I have no idea whether this is normal for old possibly dying hamsters or not.  Despite all my jokes about wanting the hamsters out of the way so we can have a cat I'm really quite fond of them and I want to help him.  However I don't know if a) you can take a hamster to the vets - I mean can you or do they just laugh at you for wasting time?  and b)  Is this actually serious or am I just being over-protective of a hamster?!  What can I do for the little fella?  Anyone got any suggestions?