You also save on carrying costs by selling all at once.

One wrong item comes up, wether it's a structural or foundational issue and your deal could be shot. 

Does she carry insurance for liability when it bites someone or kills the chickens?

The low end roofers who do not carry insurance, run their business out of their truck, and use the cheapest materials are fine with only a 25% profit margin.

Ask the seller to carry a 2nd mortgage for the 25% for a few years. 3.

The seller hasn't moved her items out and won't let me advertise it yet so I'm on hold with it. 

But they only take a write down of their inventory if their carrying cost is less than fair market value.  

And even if she can't meet them, someone (the seller or the agent or you) should be able to prepare a folder left in an obvious area that says FOR THE APPRAISER, with items like cover pages of other offers, area comps to use, etc.

Ashwin - From what I can see from your analysis I would make sure you have insurance as well as (common) utilities in your expense items.

Items like population growth, rent growth, income growth, job growth and job diversification can help in the early stages of due diligence.