You feed room temperature rodents, no wonder your BP isn't eating. BP's hunt with their heat pits. Rodents offered need to be heated to around 38 C.
There are a few ways to do this. Many people use a hair dryer, others use heat lamps etc. Any radiant heat source should work. I wouldn't recommend using a microwave/oven/stove though as you don't want to cook the rodent.
I will try this next tume i offer food i have always offered at room temperature and had no issues in the past and he definately knows the rodent is there for him.