HI, I have 25 chicks, 2 weeks old. I'm planning to take them out of the brooder, hopefully today, and let them have the run of the chicken house(the brooder is in one corner of the chicken house). I had meat chicks in there this summer, they were processed in July. I disinfected the chicken house with a bleach solution. When I was at Tractor Supply this morning, getting more feed, I picked up a Storey's book on chickens, glanced at the raising chicks section, and read that chicks should never be housed where an older flock has been, because of the possiblity of them picking up Mareks. I'm not too worried about the chicken house because of the bleach, but the outside run shares a fence with my laying flock (2 1/2 years old). I don't plan to let the babies outside until they are around 6 weeks, depending on what the weather does here, but will I need to worry about diseases passing from my older flock to the babies?? I have no reason to think that my layers have active diseases, and the meat chicks were in the coop where the new babies are and had no problem with disease...will the current chicks be ok? We haven't had a frost here yet, but probably will before I let the babies outside...will the run be safe for them? Do I need to shovel up the shavings/dirt the layers kick through the fence? Bearing in mind that they will just kick more through, with their daily dust baths... Can anyone advise?