A lot of the supplies including flowers, moss and some of the butterfly wings I use in my craft are foraged during my time spent outdoors and some are purchased from reputable ethical sources. The wings and other insects are collected after a natural death. I would never harm a living being for the sake of art or condone such acts.
I often use antlers in my work. They are ALWAYS naturally shed. The deer (and other ungulates, like elk) shed their antlers every year, then grow a completely new set. This shedding procedure takes two to three weeks to complete, while the regeneration takes an entire summer to complete — before the cycle starts all over again.