I let my 4 girls out this morning and began my daily cleaning of the coop, I found 3-4 small flies in the shavings and 1 on the curtain. I did squish them and they seemed full of blood. What type of flies are they and are they biting my hens? I keep a very clean coop and run (scooping several times a day). My girls also free range all day, weather permitting and spend little time in run mostly only eating and drinking. They only use coop for laying and sleeping. I took some pics of fly for help with identification. Thanks!