Sorry for the necromancy, but I have seen a documentary on the logistics of poultry farming on Dutch television that might shed some light onto this.
The Netherlands produces quite a lot of eggs and so we also have a large supply of older chickens that are not sold through the regular channels. The documentary makers actually managed to follow a batch of biologically fed free range chickes (doesn't get much better than that right?) to Africa (of all places) where they were sold nearly for free to the locals who use them in stews and told the film makers that the Dutch are absolutely bonkers as far as they are concerned.
As always, this type of free-market-gone-wild thing had the lovely side effect of destroying the local production, as the prices for chickens produced in Europe, frozen, packaged and transported to Africa were so low that local farmers could no longer compete.
I do buy stewing hens all the time myself though, through poulterers on (farmers) markets and I have to agree that for use in stews and soups they are by far the better option as they have better, deeper flavor and retain a lot more texture during the long cook.