You're supposed to retreat in 14 days. I am having the same problem but I have 100 chickens so it has been my life right now. I first tried the permethrin but that wasn't as effective. Now I'm doing the PSP
I already tried permethrin to treat my chickens motes and sad to say it didn't work. Treated them every other day and they still held on strong. I am using Elector PSP now.
I have been using the Permerthrin spray for mites as directed spraying every other day and I can say it doesn't work on these guys. I am still finding them after spraying the coop, ground and chickens.
We have been SO BUSY spraying our coop, ground and chickens. My neighbors' chickens have mites and lice and I caught their two roosters in with my chickens. I guess they flew over the fence. We have been SO busy my back hurts and my legs feel like they're going to fall off. We have 50 chickens...
I have not weighed them no. I really don't have a way to do it plus the calculations seem WAY too complex. I am just worried about temp and humidity and will just keep my fingers crossed.