It reads like botulism but so far he's the only one affected, he's got that limberneck thing and just lays there for the most part. He's one week old and all the chicks were vaccinated for mareks, they're eating medicated starter and the water has vitamins in it. He's not completely paralyzed he just falls over when he stops struggling. I've got him isolated, any ideas? Updated to add: There are now signs of blood in watery diarrhea. I've been syringe feeding vitamin water with an antibiotic. He is standing at times now and cheeping a little. Fingers crossed.