if you leave the wood coated with hide glue,, or really any kind of glue it will prevent the moisture from coming out the belly or sides,, and reduce your checking,,
also maybe let it cure in a more cool place,, since it winter, mabe the wood was drying too fast after the moisture induced by the sinew,,
I even read in one book,, they guy would rawhide back the belly to keep it from checking,, then take off the rawhide,, glue has worked for me,,
but i bet it was really dry where you had the bows,,,, almost like a heat box ,, and it caused it to check,, hope that helps,,