Glad to hear that you put it in its own habitat.
On the diet issue: presuming that you are cutting the chicken up into small pieces, have you tried cutting those pieces even smaller, and adding, say, finely chopped bits of carrot to the chicken bits? Or greens, or fruit?
By chopping the chicken and adding chopped piecs of other vegetables, greens and/or fruit, you will be increasing the chances of the little guy eating other good foods, if only by accident. In other words, each mouthful should have a bit of variety to it, not just one single food item.
As for the rest: as long as you have a good temp. range (cool end 75, warm end 85, or so), relatively high humidity, a shallow water 'pond' that it can get in and out of easily on its own, good light source, including uvb, you should be ok.
Turtles need a variety of places to hide, bask, soak etc., so that they can regulate their body temperature, and yes, the babies do spend alot of their day hiding.
I make sure mine go in for a soak every day, too, which isn't a bad idea for you: just make sure that you rinse the 'pool' every day, and be sure to use 'conditioned' tap water (unless your on a well). Condition the water by filling a clean container with water and letting it stand, open for 24hrs, to allow any chlorine to evaporate off.
Good luck
Stephanie