Daft question re flies on my horse's nose

[kellybee]

We currently have two horses and two ponies. The horses are rotated around five paddocks and the ponies are kept in a separate two paddocks. Poo picking is done at feed times (literally every day). There's a pond over the back of the horses' grazing, and sometimes it doesnt smell so great, but we fly mask them and spray them twice daily, going so far as to spray onto a sponge and wipe onto their noses. I also remove their fly masks and spray those before putting them back on too.

This seems to keep the majority of the flies at bay for three of them, but one seems to suffer terribly with flies all over his muzzle. I mean... DOZENS of them. He doesn't have any discharge and it's been the same all summer long. I've tried him with a fly mask that covers his nostrils but this seems to cause the flies to buzz around underneath the net, causing him more aggravation than a normal mask. On still days I've had to bring him in to escape from them all, and that's the only thing that seems to do the trick! Can anyone tell me why on earth this only happens to my one boy (He's the dark one in my sig). I'd wonder if it was his colour that attracted them but both big uns are very dark and my shetland also has a black face. I tend to hose him if he's sweated during work but I don't soap bath them often. Any ideas?

 

[Penny Less]

The only thing I can think off is to turn him out in a headcollar and attach a fly fringe to the noseband and shorten the
fringed bits, the constant movement of the fringe should frighten the flies off