Make sure the mouse is nice and warm. Bp's are pretty dumb and think it is alive if it is warm and "moving". I have two Bp's that will not take a F/T if it is not warm enough. Warm it a bit more and they go right for it. Buy a little notebook for each Bp and keep it on their enclosure. Record every thing you do and on what day for that animal; e.g. bm, urine, shed, feed, weight. That way when you forget what Bp did what on what day, you have a reference.