Boa Constrictor not Eating

Question
I've had a baby red tail boa constrictor for about 4 months, and all in all, it's a very healthy snake. Temperature and cleanliness is no problem, with the exception of having some troubles with keeping the humidity high enough. It's very alert, active, and perfectly normal, but I can't seem to get it to eat. I feed it in a seperate container usually during the day. I've tried putting tuna on the rat, and while it did seem too large for the boa, it didn't give the slightest interest in it. I've also tried feeding live, but that ended with the same results. Would you be able to give me some tips on how to get the snake interested? (Cage has a hide and is already covered with a cloth.) Thanks a lot!

Answer
Ok, you said "rat,"  have you tried mice?  Baby chicks (chickens) are also a possiblity.  Also, try at night.  

4 months w/o food for a baby boa is BAD.  Panacur and Flagyl (medications) from a vet might help, but I'm worried it may be too late...  Not eating is a symptom of some underlying problem, maybe the vet can help you find that too.  AT this point if it doesn't eat, I'd recommend force-feeding it or tube feeding.  The vet should be able to help with that as well.