I am going to be watching this thread. My neighbor keeps horse and unofficially his own private deer herd. The flies are terrible. I'd like to find a solution, too.
For the itch and the hurting of the bites, I have found that the aloe vera sold as a sunburn remedy works immediately for the fly bites, yellow jacket stings and most spider bites ... I haven't been bitten by a poisonous spider, so I can't say anything about that.\
The plant juices of the aloe vera work, too, but they leave a yellow stain on my skin. The store product doesn't cause that problem.
Smiles,
Lyn