When I published this piece in the New York Times a couple months ago arguing the large farms can, and often are, good for the environment, one of the most common comments/criticisms I received was something along the lines of: "well surely this isn't true for 'factory farms' and animal welfare." It has been hard to say much about this because the evidence was limited on relationship between farm size and animal welfare. However, I was recently alerted to this new review article published in the Journal of Animal Science by a group of researchers at the University of British Columbia.
Among their many conclusions are these:
“Farm size and animal welfare exhibit no consistent relationship”
and
“Our review does not support the contention that there is a consistent relationship between farm size and welfare on dairy farms or, indeed, other times of livestock farms. Moreover, the differences that do exist are unlikely to be caused directly by size but by other factors associated with size such as economic viability, staffing level, awareness of and exposure to emerging issues, and access to resources (e.g. time, capital, expert consultants, scientific information, etc.)”