We lost one pullet but the others pulled through with Corid. Most had bloody poop. It's been 4 days on Corid and they are happy, hungry and active again today. How long to continue at full strength? Do you do a half strength or prevention dose after? They are 7 weeks old. I'm going to keep them on medicated feed for a few more weeks. Will they be more resistant now that there had it? We need to get a few more chickens. How long to wait? Thanks!!