Sarah, the total tension on the strings of a full-size violin tuned to concert pitch is 51 pounds. That means that at least one of the strings requires a tension of less than 13 lbs to bring it up to pitch.

I cannot believe that a torquing force of only 13 lbs would be sufficient to snap a peg made of bone, so I can only conclude that the instrument makers you consulted just didn't fancy the hassle of making one.