Hi, It's a bit long, but it's the full history for better understanding of the issue. New chick parent here. We have 4 chicks ranging in ages from 3-4 months. Born in Late Feb and mid- March and raised in a Brooder in the house until mid-April. They were fed medicated chick feed and were healthy and robust when we put them into a new coop with an enclosed run. It is a Precision coop with an extended run. So they have about 15 feet by four feet during the day to run around when I am at work and they are let out when I get home and clean the coop. Due to clay soil that does not drain well, the coop and covered run are situated on cinder blocks about a foot off the ground with gravel underneath to provide drainage and hardware cloth on top of the gravel and blocks. At the guidance of another chicken owner, I put 2 inches of pea gravel on top of the hardware cloth. I put Diatamaceous earth in the nesting boxes. To clean this, I daily scoop out the poop and hose down the run. (This seems to be labor intensive and I am worried about sanitation as the water seems to run into the grass area around the coop.) I was thinking of using sand, but not sure if this is sanitary to prevent them from pecking and picking up diseases after poo. (I am worried about sideways rain keeping the sand wet.) I live in Maryland and between mid-April to mid May it has been non-stop cold rain. Due to puddles and worry about drinking dirty water, they have remained in the coop and run area and not allowed to graze in the yard. In mid May I started blending and switching over from chick feed to the finishing feed. I have not let the chicks/pullets out to graze in the grass until two weeks ago, but the weather has turned out to be hot and humid. (I am debating if I should start blending layer feed in late June or not). Because it finally stopped raining I was able to pick one up and noticed that it felt thinner than normal. In looking closely at the coop, I saw red mites on the outside of the coop run and walls. No signs of mite or lice deposit on chicken feathers. (Saw mites on the dropping board at night so assuming they are the night sucking kind.) This weekend, I treated the coop and run and surrounding area with permithian spray, spray poultry protector on the birds, feed them one day with ACV in water, then gave them scrambled eggs with some chopped garlic for two days, then gave them two days of save a chick probiotics in their water. Also two weeks ago I added two kitty litter boxes filled with sand/ Diatamaceous earth and the other sand/wood ash to self bath. I am plan to go retreat the coop and girls with a second round for mites when I get back from the conference. Yesterday (Sunday), I noticed that one of them pooped a yellow foamy poo, I think it is the thin Easter Egger, but was not able to catch her in the act. I am on a plane now to a conference and not able to be back at home for five days. I have the neighbor watching my girls while I am gone. Could this be cocci? I have seen no signs of worms in regular or cecal stools. No blood in the stools. What can I do? I have looked up liquid Corid and I can mail order it to the house so it is there when I get home. I have a packet of powdered sulfadimethoxine at the house (picked up when first got chicks, but have since read this is harsh on them.) Not sure how much to give per gallon of water for both Corid or the sulfa. The girls seem their normal selves, but I notice their feathers are looking a little Ruffled (possibly from post mites?). Thoughts? If cocci, what is the best method of treating the coop and surrounding ground to prevent re-infection. After treatment, should I find a vet to vaccinate them? I am also asking that you please rip apart my practices. If there is something better I can be doing, please let me know! We really like our girls and want this to be a success. Example, should I be on a routine schedule of garlic, ACV, probiotics? If yes how much and when? Should I ditch the pea gravel? Thank you in advance!