I suggest you check out Alex Rileys documentary 'Britain's Really Disgusting Foods'
Here's a link to the chicken portion of the show, fast forward to 1 minute into the clip. Check out all the episodes, very interesting, esp. the Sausages V Bangers bit!
Buying cheap from a large faceless supplier is not an option considering the potential shite you can end up with!
If you can find a butcher that slaughters their own animals you are on to a winner as far a quality goes!