Would a vet be able to help?

[Tigergenesis]

I have a 3 snakes I need to take to the vet for an initial checkup. But one has not eaten for me in the 3 weeks (rough scale sand boa) I've had her. She actually had not eaten for the breeder in a while either - since 1/22/04. Since 12/22/03 her weight has gone from 193g to 180g. My question is, if I can't get a fecal is there really anything the vet can do to determine if she has any health problems affecting her appetite? I trust and know the breeder I got her from (he said if she doesn't eat for me and I change my mind he'd be happy to take her back) so I'm sure he would have checked her mouth for any signs of anything (sores,etc) that may be keeping her from eating.

I'm just trying to figure out if I should wait a bit longer with her or if there is anything the vet can do at this point. I'd hate to go pay for a visit when all he can do is check her visually since I can't get a fecal. Am I worrying too much?

Thanks.