Attached house/barn

No, actually when I said ventilation I meant the common use of the term ventilation - air movement. Specifically, concerns that “toxic” gases generated in an “animal housing facility” would infiltrate the living space. One example he gave was that a neighboring county wouldn’t permit a barn with an upstairs apartment because of concerns about emissions from the barn rising up into the living space. They did, however, allow the apartment to be connected to the barn if both were built on the ground.

Chiming in from NY. We had a HECK of a time with the planning board in our area when we were building over 10 years ago. They wanted fire doors in the indoor that could be operated with one hand, cinder block walls, sprinkler systems (how that will help in sub zero weather is beyond me), etc. etc. I would think we are in a less restrictive part of NY than Millbrook.

So, to echo a lot of other posters, check with your planning board before making any decisions. King Construction out of PA does a lot of work in the area and is familiar with many of the local zoning requirements. Their consultations are free and they are super nice to work with. I would give them a ring.