None of the drops work well. If you have thick fur dogs or "real" dogs that get wet its useless. The collars are awsome. Find dead ticks non engorged not even bitten in fur. Everyone that I've suggested these to are blown away.
I want me some Guinne hens but they always get smashed in the road. Most ticks are in tall grass or leaves unmowed areas. When we get out of the woods its easily 30 ticks per dog that we pick off.
We're on 8.5 mostly wooded acres. The dogs really like wandering in there, and I've never found more than one tick on any of 'em. The Advantix II worked very well, but you have to peel back all the fur and apply to their skin. I used to put some on top of their head, between the shoulders, the middle of the back, then back by the haunches. Mostly, the ticks would be on the dogs legs. Found more than a couple dead as a doornail on the living room floor. I've found ticks crawling on a sheet hanging on the clothesline. WTH? Little devils, that's what they are.