Try putting the rat pup in an empty toilet roll tube, park the entrance of the tube right outside of the entrance of the hide his little head is poking out of.

Leave them alone, in a dark, quiet room & hopefully he will feed. If he is anything like Deebo - he is very secretive as far as feeding goes..

Well it worked for me once anyway & anything is worth a try for a non feeder!

I have just thought, you guys feed live dont you ? Im not sure if this tip would work as I have used this with F/T mice..