What is chewing stock?
“Chewing stock” refers to bees who have a genetic tendency to kill mites by chewing their legs or other parts so that they die. Mites’ blood does not clot/coagulate so they bleed to death pretty quickly. They were originally discovered in feral honeybees around Purdue University and were commonly called “Purdue Ankle Biters” by the entomology department there. They have done grafting classes there as well as off-site for quite a few years to try to expand the genetics to other areas. There are many descendants of them around now. The Kentucky Queen Bee Breeders concentrate on various versions of them, even instrumentally inseminating them with drones that have chewing tendencies, along with hygienic tendencies (so they remove mite-infested larvae as well as kill exposed mites). It’s not a replacement for checking and treating for mites, but just another tool in the kit.
If you are interested in incorporating the queens into your bee yard the KQBBAI group has a list of beekeepers who are selling mite-fighting queens in Kentucky. Or if you are interested in raising them yourself, the KQBBAI always welcomes new members – they offer grafting classes in the spring and do lots of great classes throughout the year.
Hope that helps. There is a lot of information out there about mite-chewing honeybees, including amazing videos of them actually pulling them off of bees and chewing/killing them!