Bartlett has a long-time reputation as a spinning mill where people who raise sheep go to have their fleeces spun into yarn. I once bought a few skeins of their worsted from a farm-based shop on Cape Cod; it had been made from the farm's own sheep. I don't quite know what to say about it: it was good wool, not overly processed, well spun, and it made a very nice winter scarf.
Actually, I wasn't aware that Bartlett sold its own yarn.
After looking at their Web site and their prices, I'm tempted, especially by the Shetland.