Coccidiosis not sure if my chickens have it?

It was sugested I post here. I had noticed loose stools but a little too late. Im very new to having chickens. I got 12 begining of March. They are cobbs. White meat chickens. Everything was great until Thursday so I thought. I started seeing lethargic chickens. They didnt want to eat. They started looking un kept. Wouldn't really respond at all like before. Running across yard to greet me & follow me anywhere I went. Then a dead chickenthat evening. No evident signs as to exactly why either.
Next day there was bloody stools and another hen dead.
I spent the day at Tractor supply and researching symtoms. I picked up B-12 for them.
The Saturday morning a rooster was acting very sick. Hes boyfriends favorite. I called local feed store. Lady there said sounds like worms. I pickd up Wazine and gave it to them. I had been gone that afternoon. I knew Hammer one of the sick roosters probably wouldn't make it. To my surprise he looked better but I lost one of the other roosters, Left Wing.
This moring I was greeted by Roofus the biggest rooster with his hearty new found voice of a cock a doodle doo. All eight remaining chickens looked in good health today and very hungry. They seemed very responsive as well.
I was so worried I would have to put them all down. I can't see them all dieing like that. I have a new found hope.

It sounds like the ones that died had coccidiosis. I would get Corid (amprollium, Ampromed) from a feed store and treat the rest. Dosage is 1 1/2 tsp of Corid powder to a gallon of water, and treat for 5 days. Afterward, give some poultry vitamins in the water for a few days, and a bit of plain yogurt for probiotics. Here are 2 good articles to read:
http://www.the-chicken-chick.com/2012/12/coccidiosis-what-backyard-chicken.html
http://www.merckvetmanual.com/mvm/poultry/coccidiosis/overview_of_coccidiosis_in_poultry.html

Thank you. I planned on it when they open Monday morning. I got home from work and they all but one look really good. The one that doesnt is a little runt of bunch. He's not bad like before. I can't say how much I love this site.

So today chickens looking good. I got the medicine in their food. I'm glad I haven't lost any more chickens. Four more days of medicine. I'm dosing both flocks.

The Corid seems to be working. I'm happy not to lose any more chickens!

Thanks for the update. I hope everyone continues to stay healthy. It is a good idea to give a few day's of probiotics and poultry vitamins in the water after the Corid is finished.

I have that ready to go starting Saturday. Their last day on Corid is Friday.
I have read a lot about giving plain yogurt to them. But not article gives advice on how to do it. Mix it or just set small shallow bowl of it?