Permethrin is an agricultural pesticide. Permethrin does have noted toxicity, especially in cats, and especially a noted dermal toxicity in rabbits. If people prefer to use this over safer alternatives, it's their business, but I would certainly want to know about it before I dumped it on my buns.
Incidently, the permethrin deaths caused by the Hartz products were well below the LD50 listed in the MSDS sheets.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry