Dumeril stopped eating

[djtkach]

We have a 16 month old female Dumeril's Boa, who has been a good eater on F/T rats since we bought her (spring/13). She graduated from weaned to small rats in Sep and stayed at one a week until Nov 16th, which was the last time she ate. She last shed about Nov 10, and is not showing signs of shed currently. She is very active, and is behaving consistently with before, maybe spending a bit less time in her hide than usual but otherwise about the same. Temps and humidity in the enclosure are consistent with the rest of the year.

I continue to offer food once a week with no luck. I've tried putting nose-to-nose, dangling (she never has taken to this - fear strikes then ignores), reheating the head of the rat, putting her in a hide with the rat, covering her tank with a blanket, feeding in the back of the enclosure for privacy, etc., with no luck.

Two questions:
1) How long can she go without eating before I should start to worry about her health?
2) Any other tricks to try with a stubborn dum?

Thanks!