Personally I wouldn't go to live yet. Do you warm the rats up before you feed? My water in the house gets so hot that you literally will get burnt if you leave the hot on and put your hand under it. I place a f/t rat in a Ziploc bag and run the water super hot. I fill a bowl and put the rat (that is in the bag) in the bowl and let it get nice and warm. All of my bp's have taken f/t this way, even my full grown adults that were on live.