To medicate or not to medicate?

Literally just got this rooster yesterday after our rooster got attacked my a dog. Brought him home and he did fantastic, was following me around, crowing, trying to chase ladies. Today it’s a little overcast and much much cooler than normal, so I expect the flock to chill out in their coop or in our barn. I found the new rooster laying down in the corner of the coop with his head turned back tucked into his feathers just like he was sleeping normally, except it’s midday. He let me stir him up and he trotted off but then he went back into the coop and laid down and just kind of drooped his head. My flock has 8 hens. I have not dewormed them or medicated them at all yet, they are all less than 6 months old. They had been free ranging a ton until the dog attack so now they’ve been “cooped up” in their run for a while now. I’m afraid it might be coccidiosis because his poop is normal colored but runny and has clear mucus. I did find green runny poop in the coop as well.

I guess my question is can I go ahead and medicate him and the flock for coccid now? Clean and replace everything just in case it is coccid? If it’s not coccid, and he’s just chilling because it’s cooler weather, then I don’t want to risk over medicating.

Right now he is separated since he is the only one behaving differently. I have him in the garage in a kennel with scrambled eggs, blueberries, and some scratch to see if he will eat anything. I planned on going to TSC now to get some Corvid and some electrolytes or vitamin supplements for water. But then I’ve also read for coccid no food, just medicated water?