Permethrin dust will work too.I know a dusting powder exists that can be used on them because i own it and have used it on chickens, generally though waterfowl worry me because of them bathing and it coming off into the water...
ANyways, none of mine have but it can certainly happen and i agree with others on the broody beasts being more at risk and those probably housed with chickens.
I'll also agree lol with the poster who said why did the vet not suggest or do anything? Isn't that what your paying for??