We have this problem from time to time in the shop i volunteer at. What i've been doing is continually force feeding it each time, but i try it last. First ill try different tactics such as braining, or getting the food warmer than usual (but not hot enough to cause harm) and seeing if it will take it that way. Ball pythons can be tough to deal with sometimes and from time to time you'll get a few that just wont eat and eventually die. Dont give up on it and keep trying but just keep in mind he might not make it. I've also tried day old quail chicks (frozen thawed) and that will work sometimes too. I hope he gets better for you and solve the problem. I hope i answered your question well enough.

He could just be picky too, you mentioned he's acting healthy which is a good sign. Im sure he'll eventually start eating normally. Ive experienced a lot of weird habits with ball pythons. What i will also do is cover up their eyes for 20 seconds after the pinky is in the mouth and many times they'll suddenly start to eat. I hope this helps out

have you tried soft furs ??

As stated there are plenty of things you can try. But as you know you cant force feed 'em forever. So just keep trying but if absolutley nothing worsk you may have to stick him in the freezer........

I would stop force feeding and give her time. I would definitely not forcefeed more or larger food as it should be a very last resort. Try leaving a life pinky or fuzzy, or ASF, in a small container with her overnight.  A newborn snake can go a long time without eating before they start to waste away (like 5+ months) and forcefeeding is very stressful. Obviously no handling unless absolutely necessary, maybe even moving to a smaller and more secure tub to live in. The snake may not know exactly how to eat on its own, either, if its never fed itself. 

Have you tried just Assist feeding?  I have 2 that are stubborn and I'm going to try live, but I don't breed my own and all the pet stores only have small adult mice which at hatching size were too small of course.  I assist fed them and 2 of the 4 starting eating all on their own and the one is still very stubborn about eating while the other all I have to do is get her mouth open and she'll do the rest, so I'm sure she'll start taking them on her own soon.  The other is very stubborn and there is a lot you can try, braining the mouse, live, asf, chicken broth, young quail.

If nothing works and you have to euthanize I would suggest contacting your local zoo and seeing if they need king cobra food, I'm sure they'd appreciate the donation.

You say it's not eating anything offered - what have you offered? I would suggest leaving a live pinky in overnight after not feeding it for a week or two. Make sure it is nice and dark - and quiet. It should start feeding. It may just need to feel more secure and it may only want live.

i have tried mouse and rat pups live and dead, mice and rat fuzzies, and frozen thawed mice and rats pups and fuzzies. i have left them in over night in small containers. i usually let her go a week before i try leaving anything with her. after a few tries i have been sticking pinky mice into her mouth, she will often try to work it back out,  she simply wont strike at anything to eat alone. for those familiar with new born ball pythons, shes a 24 g ball python, thats less than half the size of an average newborn ball python.  she is far smaller than most newborns. so rat pups and fuzzies are way to big.