Oh sorry, I should have been more clear.
The skeleton dogs were cast with low-temp pewter from a store called RotoMetals and the link is in the post I shared below. (Check the store pricing before ordering from Amazon because it was much cheaper ordering it directly.)
The feathers and base of the wing were cut out of wood, and then I glued them together and made a silicone mold out of that. Pewter is easy to sand, but doing it this way gave me a smoother result than I could get with making a mold of an engraving. Of course, a lot of this won’t work the same for brass since it melts at such a higher temp, but maybe it’ll give you some ideas.
This is the wood wing and wood cross glued into a box so I could make a mold of it. (I put the cross in upside down and had to mold it a second time. 
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The silicone molds.
The final metal castings.
This was my first attempt at casting.