I originally thought I would hold this until I had a chance to read through everything and vet this study, but at this rate that could be months. So I will just put it out there for you all to look at and evaluate for yourselves!
The Cornucopia Institute, an organization "promoting economic justice for family-scale farming" did a survey of organic milk companies and rated them based on their answers.
The questions had to do with size of the herd, control over milk supply, certification, whether they have a closed herd or use replacement heifers, their policies on antibiotic use, and policies on hormone treatments. The results give a good synopsis of many organic dairies in the country.