Just feed your bp in the enclosure. Feeding outside was an old school idea that has been pretty well debunked as being useful. I have a 5ftish red tail boa that I feed in her enclosure and she can tell the difference easily between feeding time and "play time". Mostly by the scent of a rat which throws her into feeding mode before I even get the cage door open. Also the problems outweigh the benefits. Try moving a 4-5ft snake that is in feeding mode plus try moving one with a full belly. Sure you can leave them in the feeding cage for an hour or 2 depending how strong a feeding response your snake has but then its getting cold when it needs the heat the most. You can use a snake stick or a rolled up newspaper or a paper towel roll to turn off the feeding response in the enclosure but like I said, my red tail who has a very strong feeding response doesn't go into food mode unless she actually smells a rat in the room. If you are worried about substrate as I am, just use newspaper on the floor before feeding or what I use is a big 1 inch high ceramic casserole dish like thing that I throw under her after she grabs the rat. My red tail wont let go of a rat she grabs for anything so I just let her grab the rat, then grab the tail, lift it up along with the snakes head and neck and slide the dish under her and plop her head and the rat into the dish and she eats it np with no aspen being eaten. I've been doing that for almost 2 years now and it works great. But like I said, newspaper on the floor over the aspen or eco earth or cypress before you feed her works too. Avoid paper towels as the covering since I have seen and read of snakes eating the paper towel with the rat since it gets scented and is soft and it actually caused impaction and killed the snake. So stick to newspaper or some other paper that is more rigid than paper towels or like I said, find a shallow dish that fits the rat and half your snake and use that.