Location of coop... Help please :)

I assume you are talking about disease and parasites? Chickens can pass on diseases and parasites many ways, through sharing food or water, eating each other’s poop, by wind for airborne diseases, or just being nearby. Some can be carried by vectors, birds or snails for example. The further apart you can keep them the less likely they are going to infect each other. It could be your birds infecting theirs just as easily as the other way around.

I don’t know what the fences look like or if either of you free range. All it takes is the chickens meeting each other through a fence or one escaping and visiting the others to eliminate all your precautions. You can try to keep yours in a sterile environment if you wish, but personally I’d put the coop where it is most convenient to you. It would probably be a decent idea to treat for mites, lice, and worms when you first get them to try to not introduce those things to your neighbors flock. There is no reason to think they are infected with any of those but I consider that a reasonable precaution. But otherwise I’d rely on their immunity system to protect them. It’s possible one flock is harboring a disease that will wipe out the other but many people buy chickens at swaps and such all the time and very seldom have a serious problem. Mites, lice, or worms are the most likely consequence if you even see a problem and those are more inconveniences that can be handled that serious threats.

Since yours are battery hens, I suggest you find out what they may have been vaccinated against. It’s possible they have been vaccinated against a disease using live virus that has made them a carrier and a threat to an unvaccinated flock like your neighbor’s. Once you determine what the vaccinations were given, if any, research online to determine if they are a threat. Not only could you be putting your neighbor’s flock at a risk, you may be unable to add any unvaccinated chickens to your flock in the future. I don’t think it is likely they will have been vaccinated with something that makes them a threat, but some are. I consider researching their vaccinations a reasonable precaution.

I’ve probably made you a bit nervous about this. That’s not my intent. The odds are pretty high that everything will work out fine. You should really enjoy your adventure with chickens.

Good luck!