The 'Farmed Animal Welfare' wiki page on the EA Forum defines factory farming as being farms where can involve "intense confinement, inhibition of natural behaviours, untreated health issues, and numerous other causes of suffering"
However, confinement, inhibition of natural behaviours and treatment of health issues are not binary values, they are sliding scales. This is easy to see with 'confinement' - we can measure the size of an enclosure that an animal is being kept in. 'Health issues' is harder to quantify, but could be done with various metrics, like how many animals experience disease, and 'inhibition of natural behaviours' could be measured by things like time spent outdoors, amount of space, or access to an appropriate amount of their kin.
There must be a point at which a farm is sufficiently cruel to animals on all these points that it can be defined as a Factory Farm, and conversely there must be a point at which a farm can no longer be defined as a Factory Farm. My question is: Where is this point? How many square metres, or hours spent outside, or medical treatment per animal, is sufficient for a farm to not be considered a factory farm?
The answers to these questions would have big outcomes on statistics like 'x amount of animals live in factory farms'. This seems like it should be an obvious point, but when I've read articles that quote these statistics, I haven't been able to find out how exactly they define a factory farm.
Reese, Jacy (2016) Why animals matter for effective altruism, Effective Altruism Forum, August 22.