Bald, red vents

[rmir9]

I have 13 chickens, 7 white leghorns and 6 black sex links. All have this going on. Started with just a couple of sex links and now all have it. At first, I though it was vent gleet. but did more reading on here and researching it. Then though it might be lice and mites. I dusted them monday and cleaned entire coop. Inspected all birds before dusting but did not see any bugs. At this point, I have no idea. Been looking for pictures of chickens with the same thing going on but really couldn't find anything close. This closest I found was some chickens that had ascities. Not sure if thats what is going on here or not. Egg production is still up. They eat ok, some days more than others and drinking plenty of water. Any help would be great! Thanks.