Worm medicine?

I've never heard of giving chickens a vaccine for worms. But, many people do deworm their birds with a dewormer. All chickens have worms, unless they are raised on wire, so deworming is usually a good idea. Many people never have any problem with worms, as their chickens are healthy and strong and can resist the worm infestation. But, it is better to deworm, in most cases. Even if you never see worms in the droppings, your birds can still have them.

Usually, you should deworm twice a year, in the spring and fall. Two good dewormers to use are Safeguard for goats and Valbazen. Both can be purchased online and you may be able to find them at a local Tractor Supply Store or another livestock supply store. Don't get Wazine; it only kills roundworms. I recommend staying away from "natural" dewormers. These usually work better as a preventative, and won't treat an actual infestation.