When mine were that size if they didn't eat the pup, I tried again a few days later. Eventually everyone ate them (after much staring over them). And when feeding live I have the weaned ones that run right up to the snakes and scare the crap out of them. I usually shoo the rat away then leave in for a few minutes more. Certain snakes will get back to food mode once the rat is away from them and others are too "traumatized" by their meal touching them I have to try later. I'd say wait till next feeding day and try again.

Josh- a lot of breeders start BPs off on mice because the size they move around at is smaller and more appropriate for hatchlings than a weaned rat. Some BPs just need that prey movement.