Wow...that's pretty crazy. Good job on helping him out. Lots of people start hatchlings out on small mice. I've started most of mine out on them and never have had a problem. It may just be a fluke thing??? It was probably the last thing on your mind but I wish you had snapped a pic. I'm having touble picturing what you described. Give him time to recover and digest and try again. If you can, try to pick out the smallest mice. Both "pet stores" I go to for mice are good about picking out the small ones when I ask.