I posted about this a while back. We had no idea what it was used for, except a shed, but thought it had to have some other purpose. Well, after talking to the PO's family we solved the mystery. It was a smokehouse! She said they would smoke meat in there...sausage and things like that. This was a fully functioning farm so this isn't really a surprise. In fact I'm surprised we hadn't thought of that. Our house is on a highway and she said that people would stop every once in a while to tell them the building was on fire and they would explain that it was supposed to have smoke coming from it! Also found out the building is made of white poplar.
I also learned that the outhouse was located close to the far end of this building about where the clothesline is at. Just realized you can't see the clothesline because of the big tree in the way...trust me, its there. I've had people tell me that if you can locate and excavate the outhouse or "privy" that you can learn a lot about the the property all the way back to when the hole was fist dug. I'm sorry, but it was in use till the 50's so I don't see us digging it up any time soon. But it is nice to know where it was.