How I did it, Skullie, to avoid chipping, was to place the bone on a block of wood (assuming it was flat scale.
If it was rounded, like walrus or antler, then I put it in my vise seated in a sliver of PVC I cut on my bandsaw to mimic the curve, and let that act as a backer of sorts to avoid the drill "busting" through the back side.
I also think the type of bit you use can have an effect on how it works, as well.