Last night I found one of my girls acting very weak and lethargic. She is 5 weeks old and she was lying in the back of the coop, feet stretch to the side. All the others were in the run. We pick her up and she was wobbly on her feet so we put her next to the food and water. An hour later she hadn't moved. After reading some other posts on here, I'm very scared she is really sick so we have put her in a cat crate and isolated her from the other girls. She was vaccinated for Mereks at the hatchery and they are on medicated chick feed. She slept in the cat crate last night and did make it through the night. Today we put the cat crate in the brooder to see if she would like more room to move around. She immediately came into the brooder and is eating her crumbles and her poop looks normal but she still isn't very active. Any advice/ suggestions would be greatly appreciated. Am I over reacting? Should I worry about the others (they all are active acting normal)?