Problem with my King digesting

I bought my king about two months ago and I fed him two pinkies that day.
He digested those and deficated normal, but since then when I feed him and he deficates the whole pinkie in 2-3 days without digesting it. But a couple days after I find the pinkie there is fecal in his cage. He has proper lighting and heat. can someone help me with this?

It's unlikely that he's passing the pinkie whole, it just can't go all the way through the digestive tract like that.
I'd say he's regurgitating it.
Give him a week to 10 days with no food, then offer the smallest pinky you can. Make sure the heat is adequate and leave him alone until he defecates. Wait four or five days and offer another real small pink.
Once the regurgitating has stopped you can gradually go back to normal feeding.
Repeated regurgitation is a dangerous situation that can lead to death if not corrected. Just use patience and small meals to get him back to a normal routine and give him time to rest his system between meals.

Just a couple of questions.

What is the correct heat for your king and how have you determined what it is in the tank with the snake?

Is the entire cage heated or is there a warm end and a cool end?

What kind of king is it and do you know if it's captive born or wild caught?

What are you using to heat the cage?

This information will help.

thanks,
Wes Pollock