I have a male 09 500g in the same conditions. I've tried everything to get him back to eat regularly but nothing. I was successful in getting him to eat a mouse now and then (He always ate rats). He ignores his usual rat, and not interested in the ASFs.
Some people have say is just the breeding seasson probably and he will eventualy start eating again. I have my fingers crossed... is my first winter with BPs.
If you are worried about him eating. Try feeding him a live mice and if he eats it, try a second. Is what Im doing now. Most of the times he refuses, But sometimes he will eat one, and when realy lucky he will take 2. At least I know he wont starve.