Alright, @sylviethecochin, I'm doing it! I'm going out to the breeder on Monday and getting 6 (non-vaccinated) chicks of various breeds and ages 5 days to 2 weeks old. I'm using the mother hen pad and keeping them inside for a few days, just to keep a watch on them before I put them out. Then they're out in the run, separated and safe from the big girls until it's time to integrate. Do you usually keep your chicks indoors or do you do an in-run brooding? It's how I did my last batch and the integration went so smoothly I swore I would never do it differently. But that was before the Big-M diagnosis so I'm not sure if it really matters - they'll be exposed sooner or later, right? I'm just curious what you do...
I do in-run brooding when I can, but I do live in PA, so if I brooded most of my chicks outdoors from the start, they would just die (I prefer not to use electricity in the coop.)
I really prefer broody hens, partially for that reason.
Though I've been told that chicks are more susceptible to Marek's than adults are (haven't built up any natural immunity) I've only ever had one get it as a chick. I'd probably just brood them in the run.
Good luck!