preventatick used to work good but then they made it a flea and tick collar that doesnt work, i have tried advantix but that doesnt work, if you have one where you can see dead ticks on the dog let me no. I tried with 100 guinea hens a couple of years ago, they worked great but the noise drives you crazy, along with the fact they dont no how to stay out of the road or neighbors property up to a mile away.