Should I treat again?

Our chicks/pullets are 11 weeks old. About 4 weeks ago, we had one unexpectedly die. (just woke up in the morning and one was dead) Found some blood in some droppings and immediately started the other 8 on Corid. They almost all had developed some blood that day. They all did great. I treated full strength for one week and then prevention strength for another week.

Also, their poops completely changed into what I would think as "normal bird poop." I know there is a huge variety and I have looked at those gross charts. However, these are our first chickens. Before I knew they were sick they all had kind of runny, sticky, smelly, light brown poops mostly. (like a cecal poop but it was the majority of their poops) After treatment, it was much more normal.

Anyway, they are off meds for 2 weeks and they are no longer on medicated starter. I went out today and noticed a bunch of that icky stuff from before I knew they were sick. They are acting normally but I'm worried they are getting sick again. I don't see any blood but I didn't see any last time until one was dead.

What would you do?

Your choice but I'd hold off. I'm not big on meds. They should be resistant by now. Be ready if you notice drooping, ruffled feathers and loss of appetite.
Have you given any probiotics?

I had given probiotics but then I stopped them already. I could add some back in their water. I also have the electrolyte packs.