I'm surprised your boa is so picky. Both of mine would eat a paper towel tube during an earthquake if I rubbed it on a rat. My BP is even worse, she would eat in a shoebox on the way home from the store after buying the rat. Its good though that you found the rat a home, he just won the "life lottery"
Lol I thought this was the boa part of the forum, omg lol. Since that isn't the case, I can see a BP being picky about F/T, although like I said, mine eats anything...fresh killed, F/T, feeding tongs, my hand or fingers...