My baby hognose wouldn't eat the large pinkies I was trying to feed, even though they were size proportionate to his body. As soon as I switched to day old pinks (teeny pinkies), he hammered two in a row. I guess he knew more about what he could handle than I did!
Then there's my snow corn baby who attacks the large pinks like Godzilla, but can't keep them down. Now he's on teeny pinkies and it seems to be ok.
You just have to wonder about nature.....