The one I have was labeled as horse fly spray also. It cost me under $10... I have used it on my 3 med/large dogs, 2 large goats, and 25-90 birds (depending on season) for more than 2 years and still have a fair amount left (starting year 3 now). That's including spraying my floor and lay boxes and roost (even though they are already free from roost mites which live under and in cracks of wood and ONLY come out to feed on chickens at night) in my 2 x 144 sq ft coops and my two smaller tractor (coop portions). And the walls of my goat barn... since it was bought for mosquitoes and the other treatments discovered were a bonus. I will note that I refuse to "just schedule" treatments (of any kind)... as I won't treat for what I don't have in order to help avoid resistance to the medications. I NEED them to work, when needed. And I have safely used this on broody's AND their chicks! So I treat only if I see reason or symptoms, though I do monthly after dark checks in addition to daytime check on those that are lap birds. Some environments will have a much heavier load than others. And some may have heavier seasons. Climate is a huge factor.... It's so interesting to see the proliferation and subsequent void of certain things throughout the year... I've NEVER seen a June bug in December, for example.