Mez, just get some Sevin Dust at your feed store, Walmart, Home Depot, or any garden/hardware store. Dust ALL your birds and the coop, nest, everything. Then do it all again in 10 days to get the new hatchlings.
The dog stuff recommended is Adams Flea and Tick Dip. Mix it as directed and dip ALL your birds up to their "necks". Then put them out in the warm sun to dry. Do it on a warm day and early enough so they can be completely dry before roosting. Use the same dip to spray the coop, nests, everything. Ya don't hafta spray this again for months.....P