Was looking for alternative to ivermectin, found that people give cigarettes to animals to eat to deworm. Goats, horses, etc. Basically tobacco. They said leaves would be better than ciggies but cigs will work, don't eat the filter.
Like some people advised, instead of cigarettes use the roll your own kind. Also I've heard that American Spirit cigarettes do not have additives. And it is true you can poison yourself with too much of this, most of the things I read are talking about 1 cigarette or less depending on the size of the animal.