It makes complete sense to us that animals raised eating and acting the way they traditionally have been treated make better food. Evidence is sometimes hard to come by since these producers are for the most part, small family operations and lack multi-million dollar lobbying and industry organizations.
We strongly believe that the husbandry and diverse food choices, in addition to exercise makes all animals healthier, including livestock. Just think how healthy you would be if you were confined to a cage just slightly larger than you were (how most chickens and pork are raised).
For example, the following chart shows a comparison between conventional cage-raised grocery store eggs and free-range eggs.
For more information about eggs, see information from the University of Michigan.
Likewise, there is mounting evidence of a connection between mental health and diet. A number of recent studies have indicated a link between a healthy diet and mental health (depression ADHD, Alzheimers).
For example the report said chickens reach their slaughter weight twice as fast as they did 30 years ago, increasing the fat content from 2% to 22%.
Industrial chicken culture has also altered the balance of vital fatty acids omega-3 and omega-6 in chickens which the brain needs to ensure it functions properly. Pastured poultry has been found to have elevated levels of omega-3. See a story about the study from the BBC.