You may also want to try just not cutting the worms into pieces. Remember Pixies are evolved to be extremely tough and eat beastly amounts and sizes. I had the same problem with my baby Pacman so I tried giving the worms full and she ate them down with ease. There is no risk of choking in my opinion. The worm was probably 4 inches and the frog maybe an inch. They know what they are doing and how to handle the worm properly. They do it in nature just fine.