Also, when mine does skip a meal or two - feeding a female rat nearly always works... I keep records of size and gender of prey as well as date fed, and he refuses on male rats about 5 out of every 6 refusals since I got him. He also started refusing every rat from big cheese rodents, and his skipped meal frequency dropped once I started getting rats from Perfect Prey.

I will note that most of these refusals / mini-fasts that only involved missing 1-3 meals...but male rats seem to be his least favorite. I tend to save the females from each shipment and feed those after he has missed a meal or two.

Maybe yours also has gender bias