Poopy Cornish X butts, is this normal?????

[tbelcher]

So I'm totally new to the whole raising chickens thing.... I've got about 2 dozen laying chicks and 13 Cornish X. 3-5 of my Cornish X have butts like this... within the last 2 weeks I lost 2 (none last week) and have since treated with 1/2 tsp. Corrid in 1 gal of water for 5 days and medicated chick food. I wasn't feeding them medicated food before then. Is this normal for Cornish X to have poopy butts like this? Do they still have cocci?? They started going outside a little bit last week. Should I continue feeding the medicated feed? I just bought a 50lb bag of it today because they ate the other bad, but I'm concerned about the poppy butts.

 

[CityFarmer202]

My Cornish x are about 41/2 months old now, and we butchered two. 4 of my 7 had the same thing, though, i never lost any despite it. 5 of my 15 layers also had this when they where young, and i never lost any of them either. I was worried about it too. Anyone else with more experience on this know what it is???