Yes, there have been recent studies and tests that show that hens who are kept on pasture and are eating bugs and grass have a higher level of omega 3's, lower cholesterol, higher vitamin A and D etc.
ANY meat animal that is allowed to forage on good old grass will have a higher level of omega 3's and 6's in the proper proportions. It's just how nature works. I saw a commercial from one of the big meat producers about feeding their hens marigolds to make a more golden appearance. Heck, let them eat grass and that will happen naturally.
Mother Nature made the chicken to be a foraging creature. To wander around and eat as they go. I personally think that if we can keep them as close to that model things will go the best for them. Of course we also have to protect our investment. Just about everything out there thinks that chicken is just tasty!!