I have read that a pinkie is okay VERY VERY RARELY. From what I understand the pinkies bones are not yet developed and are still cartilage. The dragon must be completely full grown and it HAS TO be a pinkie, nothing bigger because the dragons cannot digest bones. I don't think I would ever do it, even when my girls are big enough because I just don't want to risk anything happening. I would try to figure out why he's not eating before trying that. Maybe there is already a digestive issue, in which case, it would become much much worse. Like I said, I am still new to this, but I have been around animals my entire life and have worked for a couple of different vets, so I have a basic understanding, the rest is thanks to Google and this page! LOL! I hope someone with more experience can give you a more definitive answer! Good luck 
