I'm doing ok considering
Normally I limit the time that a food item is left with a reptile is overnight. With newly hatched corn snakes I would remove the pinky in that time frame.
The beauty snake was being assist fed for months and was around 20g (hatched at 12g) when I left the pinky in her tub for over 2 days mainly out of frustration. I rarely give up on a life that is in my care and that I produced but at the time I needed to concentrate on my health, Pams health and a tragedy in the family so I threw the pinky in her tub and said eat or die! Terrible really but it paid off. I don't know if the decaying mouse was the trigger or she just needed a longer time to feel comfortable with it. The next few feedings went the same but now she will eat within hours of feeding.
Of course when digesting their prey they are also digesting whatever is in the prey's belly and intestinal track (yes feces
uke01: lol ). At 20g and quite a few assist fed meals the beauty snake had a more advanced digestive track than a newborn. Again, with a hatchling I would limit its exposure to the pinky to overnight.
I talk a lot about stress and its effects on reptiles and amphibians. After so many years in herpetology I've learned that stress is the #1 factor with reptiles failing to thrive. This is especially true with wild caughts.
My simple and highly effective way to feed corn snake hatchlings for the first few times is this. Upon hatchling completely out of the egg I move them to a shoe box with moistened moss and do not disturb them other than checking their environment until they have absorbed their yoke and had their first shed. A few days after the shed in the evening I put them in a deli cup with holes and put a pinky that has been thawed in very hot faucet water into the container. I put the containers into their shoe boxes and back into the rack. I do not disturb them until the next morning when I remove them gently from their deli cups and return them back to their shoe boxes. I take away as much stress as possible!
I personally believe that most of the issues with hatchlings not eating is due to the keeper being stressed out trying to get it to eat in turn stressing the hatchling out!