About 4 weeks ago, I purchased 4 Australorp pullets and 3 Production Red pullets from my local feed store. I noticed that one of my PR pullets was acting lethargic about 4 -5 days ago so I separated her into her own brooder. The next day, another PR and an Australorp was acting the same way. So, I have these 3 chick in a broodr alone and they no longer get up and walk around. Most of the time, they are laying on their sides. They hobble to the water and feed, but then hobble back under the light. I've put Pedialyte in their waterer being concerned that they may need some electrolytes. I have also been getting them out to see if they will walk. At first, they lay over, but after I mess with them for a few minutes they will start to stand and sometimes take a few steps. But, for the most part, they are spending their days laying on their sides. After getting online and researching a bit, I'm still just as confused as when I started. I feel like Marek's is the culprit, but I'm not sure. What does this sound like to y'all?