So I'm very new to chickens. This morning I went to go check on my flock (2 hens, 8 chicks who are about 9 weeks old). One chick was dead, one was lying on the ground and seemed to be paralyzed (when I picked him up he pooed on me and it was liquid), and one now seems to be losing control of his neck (it's tilted to the side). I really need help figuring out what this might be. I'm terrified that I'm going to lose everyone. They all seemed fine yesterday! They seemed to be eating and drinking fine I did some research and I feel like Marek's might be the cause but I really am not sure.