I do not think it is very possible to force-feed a pinkie because it is very difficult to prop open a hognose's mouth.
It's time for drastic measures.
I have actually found baby hogs quite easy to force feed due to the fact that they will play dead if stressed. I find that if you take a small dead pinkie (place it in very hot water for a few minutes to cook it - it will be firmer that way) and try to place it in the snakes mouth, the snake will struggle and eventually play dead.
Once it begins to play dead, then you simply place it back in its cage carefully, open its mouth (should already be open since it is playing dead) and very gently put the head of the pinkie as far back in the throat as you can easily place it. Then very carefully put the snake down (upside down of course- it is still "dead" ) and quietly and slowly walk away. I have found that when the snake "comes around" and finds a pinkie halfway in its throat, about half the time it will just go ahead and swallow it.
You have to be patient and not disturb the snake at all during the process. Just turn off the lights and go in the other room for 10-15 minutes. When you come back the pinkie will either be gone or possibly have been spat out. If the latter, give it one more try. If it doesn't work the second time, try another day. The trick appears to be to get the nose of the pinkie back into the throat a little, not just in the mouth.
Of course, this may not work if you have been handling the snake too much (it will be reluctant to play dead). That's why I don't handle baby hogs until I am sure they are eating predictably. I need their defensive reactions to work in my favor sometimes.
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Chris Harrison