I've got a moose rack that I would like to mount but one side has a portion broken off. I've heard that epoxy putty can be used to fill in the defect. Is this the best option and how do you hide the seam where the epoxy meets the antler? Can you buy the putty at a hardware store or do I need to buy itfrom a taxidermy supplier?

There is a product on the market called Magic Scupt. It is made by Wesco in California (916)-635-1270 and is great for that application. We use gallons of this stuff and it does come in small kits. It gives you about a 4 hour working window and is easily worked like clay. With a little warm water you can blend it in so you won't see the seem at all. Then we color it with some oil paint(comes in a tube and you can get it at any craft store). The good thing about oil paints is that you can put it on heavy and blend it down with a rag or paint thinner. Good luck!