Rancor pit bone

I've been trying to get a replica bone that Luke Skywalker uses to fend off the Rancor in the dungeon in ROTJ. One of our 501st members was a butcher and was going to help me out by getting a horse femur or something, as it should be about 3 feet long, and a cow's might be large enough.

Any suggestions?

i work in a butcher shop and we get cow femurs in all the time, they are roughly 1.5-2 feet long.

pink foam and a hot wire..bondo, sand , paint