How does the town define "permanent"? I always thought it meant a structure that was on a foundation. Without trying to stir anything up, perhaps you could ask to see the rules for better understanding. It sounds kind of fuzzy to me, mixing apples and oranges, ie chicken legality vs structure legality. As somebody else said, is the structure only illegal because the chickens use it? If the chickens hang out on your deck or you bring a sick or cold one into your garage, does that make your house illegal? But I guess if they're giving you a variance, they can ask for whatever they want. Good luck and if they do grant you the variance, make sure everything is spelled out clearly so nobody can get you later! I like the idea of putting the playhouse on wheels to make it less "permanent." And just because the structure can move, does it mean you actually do have to move it? Will they tell you how frequently it has to be moved or where it has to be moved?