We feed in tank, simply for the fact that the one time we tried the feeder box, he regurgitated his food. I'm sure it's because of the amount of people we have living in our house, and the fact that it's an old house. We feed live, and use tongs to hold the mouse (so substrate doesn't get into his mouth). We've tried feeding F/T, and he won't take it. He was a rescue, and I'm almost 100% certain he's eaten live his whole life, and he won't eat anything else. I suggest using tongs to reduce the amount of substrate that gets into your BP's mouth.