I was at the Saratoga Farmers Market this morning, and noticed that at least two of the vendors sell grass-fed meat. One is Lewis-Waite Farm (from Greenwich NY) and the other is Marilyn and Arnold Grant Farm (Argyle NY). Possibly other vendors as well, but I usually buy from these two farmers.
And BTW, the Farmers Market is open all year. In the winter it is at the Division St. Elementary school. (The winter market mostly has meat, dairy, eggs, apples, and root vegetables. Also some handicrafts. A few farms have greenhouses, so there are a few greens also available.)