We have miniature donkeys that love them but we get them for our sheep. The sheep love them! I just show them one and they will follow me anywhere I want them to go! Hard to find treats that do not have copper.
I love NickerSnax. I have been using them for years. My three horses all like them and I can keep them in my pockets without them crumbling or getting sticky. They don't mildew and I store them in a plastic container in the tack room at summer and winter temperatures with no problems.