Salt and Pepper - it is common practice among some dog breeders to place a tray of bleach water next to the doorway into their kennels in an attempt to prevent cross-contamination. All who enter must step into the tray before entering the kennel. In your case, it might be useful to place such a tray to step in outside the neighbor's chicken run, another at the end of his driveway, and maybe even a third at the beginning of yours. Leave a few pre-mixed gallons at each location. Don't dump it on grass.
If you decide to treat his flock, you should tell him. I understand your reasoning, but at a certain point you have to be honest and tell him you are worried about contamination potential, that you have already treated your flock, and whether it's his birds, or the native soil harboring some infectious agent (most likely), if your birds are better after treatment his will be as well. I assume you would use a water soluble broad spectrum antibiotic commonly available at the local feed/supply store?
I have read several times that certain places harbor Marek's. If the soil in your locality is one of those places, and I believe such places are numerous, then the birds that are still alive have developed immunity, whether inborn or through recovery from infection, or they were vaccinated as chicks. I have also read that one can develop immunity in the flock by running a turkey or more with the chickens, but have not tried it.
If you decide to treat his flock, you should tell him. I understand your reasoning, but at a certain point you have to be honest and tell him you are worried about contamination potential, that you have already treated your flock, and whether it's his birds, or the native soil harboring some infectious agent (most likely), if your birds are better after treatment his will be as well. I assume you would use a water soluble broad spectrum antibiotic commonly available at the local feed/supply store?
I have read several times that certain places harbor Marek's. If the soil in your locality is one of those places, and I believe such places are numerous, then the birds that are still alive have developed immunity, whether inborn or through recovery from infection, or they were vaccinated as chicks. I have also read that one can develop immunity in the flock by running a turkey or more with the chickens, but have not tried it.