....
My garden (and home) is being invaded by horse flies (three horses are
stabled in the field next door) and their nasty bites make venturing
out into the garden quite hazardous. Is there anything I, or the horse
owner, can do to reduce their number? TIA.

there are plenty of things that the horse owner can and should be doing,
maybe they already are. Many lotions potions and rugs are available to
put on the animals, it goes without saying that the stables and horses
should be clean. It is an unfortunate fact that some horses get bitten
more than others, the flies used to love my old horse but they are not
interested in our present pet.

kate