I'm not related to the Zuill family, but I'm living in a Zuill house (of sorts).
The building lies one mile over the Rock County line (in Walworth County) and is, therefore, one mile from Johnstown township. Sometime prior to 1910 my home was "Zuill & Shephard, Makers of Creamery Butter."
We found cancelled checks for the creamery in the attic insulation several years ago. The earliest date is April 1910, and the check is signed by Stewart and Chapman, which also reads across the top. The top is actually glued over the previous owners (?) names, Zuill and Shephard.
Would love to know if your Zuill family was in the dairy business and if there's a possible connection . . .