One more thing about the Deet. Regardless of what others may tell you it will not hurt your birds. I've used it for several years now. I keep around 400 to 500 chickens year round; sometimes more, sometimes less. I use the Deet on them all twice a year. saladin
There are a number of chemicals available in the US, but I'm not sure about Canada; you'll just have to check.
I'll just list a couple:
Malathion
Pyrethrim (available as a spray for dogs: works fine)
Personally, I use Spray Deet. It is available here at Walmart or any hardward store. I think...