I have a 3 month old BC Marans roo that started limping a couple days ago. He's eating well, and crowing, but I noticed today he is holding his wings funny intermittently. He's in a barn that has 3 large coops. There are about 70 young chickens in these coops, most 1 to 2 months old, but two pullets are the same age as the roo. If this is Marek's, is it too late to vaccinate? How can I prevent the rest of my flock from becoming symptomatic and possibly dying? What do I do at this point? The barn and coops are brand new. And the birds have not been outside yet as we haven't finished their runs. I have a flock of laying hens in a separate house. Is there any way to protect them? I really need some advice here please.