They are little round bugs that don't have wings.Location does helpFrom what I understand the gnats are pretty rough this year. I think every year there are deaths, but some years worse than others I suppose. Either way, sad news for the backyard keeper. I don't know if that's what is biting/swarming @Ms Clucky but my understanding is the gnats like to bit anything.
https://www.backyardchickens.com/threads/gnats-killing-birds.1305726/
https://the-chicken-chick.com/protecting-chickens-from-killer-black-flies-buffalo-gnats/
https://blog.mcmurrayhatchery.com/2...-alert-black-fly-buffalo-gnat-poultry-deaths/