This time of year I think I'd bring them all in, with the runny swollen eyes and flies I think it'll take ages to clear up if you don't. When my flock had it it was around lambing, some of the ewes went blind which was awful to see, but the advice I had was that you can spend a lot of time and money treating it, but it will last for as long as it lasts. As with Orf, leave it along and let it run its course.