1) The eggs and the meat from pastured chickens is higher in vitamins because they are fed their natural diet. Insects, grass, etc.
2) Grain fed meat as a ratio of omega 6 that is pretty whack (sometimes as high as 16 omega 6 for 1 omega 3). The problem is not with eating fat but eating the good kind of fat.
3) Again, wild game or fish have more vitamins because the are fed their natural diet. They also live in a stress-free environment with lot of sun exposure and activity.
by buying any of the above (cage free hens and their eggs, and wild caught animals) you will probably support smaller farmers. Animals taste good but they dont deserve to be mass produced. The way my parents raise their animals (pigs, rabbits, duck, etc) is pretty natural. not only do I know that there is an added nutritional value to the meat, but it also taste much better.