I wouldn't worry about the insurance company. They like to come out and make sure you aren't doing anything with the property that will increase its risk. For example, if you have one of the breeds of dog on their dangerous breeds list, they could drop you. Or if you added a sliding glass door, that will up your premium. New buildings may increase the amount of your premium if you want them covered on your policy. So if you want your coop(s) covered, they will see them and add to your premium; if not, you can elect not to have them covered. As long as they don't pose a risk to the property that IS being covered (example, shared roof and you use heat lamps in the coop that could potentially set the whole house on fire), you can elect to have them not covered and it won't change a thing.
Also, you can appeal anything. I recently had an insurance inspector come out and the next thing I knew I got a letter saying my premium was increasing because the sq. ft of the house was higher than I had stated. I showed them the property tax records indicating the sq. footage I am paying taxes on, told them that is the figure I had used, and my agent sent it into the higher ups and my appeal was successful on the grounds that if the county assesses property taxes on the lower number, it is likely to be accurate since the county wants to collect all the property taxes it can. They also tried to add on an addition for my "sliding glass door". I pointed out it is a French door. Told them I can take pictures of it opening or they can come out and walk through it if they want to. They took off the addendum for that too.
Last resort - you can always change insurance companies.
What about building some hoop coops to separate out your species at breeding time? I recently built one and plan to build a second, thinking to put turkeys in one and ducks in another during breeding season. They go together fast, are sturdy, don't cost that much to build, and look good (IMHO).
