Well, with that layout it was guaranteed to happen. If the feather had angled up or down, no problem. But the way that was laid out, the grain was perpendicular to the wrist and the resulting strength was only 5% of normal according to Mark's Engineering Handbook. Any side force like a drop or a fat Lab sitting on it was a guaranteed break. You need about 5/16" pins and strong epoxy to fix this. Some can do it so well, you wouldn't be able to tell it yourself. Others are not as good and it will rebreak.
Here is a proper feather layout: http://www.doublegunshop.com/hiatt/hiatt01_102499.jpg

Remember that 5% when you buy a gunstock