I have Marek's Disease in my chicken flock. I also raise pigeons. I've done, and am still doing, tons of research on this insidious disease and nowhere have I found any documented incidences of pigeons contracting it. From what I've read about Marek's, quail can contract the disease naturally and turkeys can be infected experimentally with it (although clinical cases have been reported in Europe). Scientists will also inject turkeys with the turkey herpesvirus (HVT), an avirulent strain of Marek's that is commonly used as a Marek's vaccine for use in chickens. An interesting side note on this is that turkeys shed a version of this 'vaccine' in their poop and so chickens that have always been raised free range alongside turkeys rarely, if ever. contract Marek's Disease. This is thought to be because of the way chickens eat while out on the range. They scratch and peck, so some turkey poo can't help but get into their beaks and get eaten and digested. Therefore, those chickens who have acquired their strengthened immunity to Marek's (albeit a la natur-al) have the same risk of getting Marek's Disease as those that were vaccinated using the standard method. But beware...turkeys raised with chickens oftentimes come down with Blackhead Disease...as lethal to turkeys as Marek's is to chickens (and apparently quail also) !!!
