I have been experimenting with clay and metal for years.
My clay horses and elk have steel wire in the legs. Landscape staples and tent pins are made of steel. They can fire up to cone 06.
I also fire steel carpet tacks for accents and "eyes'. They too fire to cone 06.
If you want the legs to look like copper, use Amaco rub and buff.
Copper will melt so the antlers are added after firing with Bray Patch.