Tosha is right, try something with a little bit of fur on it (at least until they take a few meals). It usually only takes two or three meals before they seem to get the hang of it and stop being so timid with their strikes.
I also start them on live rats. At this point in their development it is still rather easy to switch them between frozen-thawed, fresh killed, and live. You can also try mice - even if you plan on feeding rats later on, like I said, they are easy to get to switch to whichever prey items you prefer once they get past their hatchling timidness.
Assist feeding is also something you could attempt. (Notice I said "ASSIST" feeding not "FORCE" feeding). Sometimes the little buggers seem to require a little something extra to get them to start eating. If it comes to this, I will take either a fresh killed or frozen thawed rat of appropriate size (if you are doing this it is almost easier to use rat pinkys instead of fuzzies). I then gently (but firmly) grasp the hatchling just behind their head and lay their body on something to not only support their body but also to "pin" them down (they will thrash quite a bit). Grasp the rat pink in a similar manner and gently use the pinks nose to "pry" open the hatchlings mouth. I usually place the pinky's head almost to the hatchlings throat.
The hatchling will most likely try to "spit" the rat out of it's mouth. To help prevent this, I gently squeeze down on the snake's snout and lower jaw and then give the pinky a slight tug or two. With the snake's recurved teeth this will help to "lock" the pinky in the snake's mouth a little better.
After this, I simply place the hatchling into it's tub. Generally, they will try to get the rat out of their mouth for about 5-10 seconds. If they succeed at dislodging it, so be it. I leave the rat in there overnight and about 50% percent of the time it is gone in the morning. If they can't dislodge the rat in this first 10 seconds the will usually stop trying rather quickly and usually (about 90% of the time) they will begin consuming the rat.
I've only had to resort to this method about a dozen times or so, but every single hatchling that I've had to do it for has begun eating (striking and constricting of it's own free will) after only one or two of these assist feedings. After that they are ALL little garbage disposals.
However, this shouldn't be used right off the bat. Give them plenty of time and use up all of the tricks up your sleeves a number of times over before even trying this. Some just take a little longer to come around than others and it doesn't pay to stress them out right out of the gate. Give them time - something you do today may not work, but might be exactly what entices the little bugger tomorrow (literally).
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I'm still not sure if it's weird that my best friend is a two year old boa named Ronin. He's quiet, non-judgemental and listens... what more could you want?