you will find you can get away with a lot of chicken even 2 days later, the sell by dates etc listed take into account that it could be stored at the minimum fridge temperate, where most people dont have their fridges that low.
Iv eated most meats 3-4days past sell by just because iv got fridge turned quite high, and i thoroughly cook stuff.. and iv got a nose to smell, thats usually the best bet, smell+feel, usually easy to tell when somethings off, if its slightly off and undetectable through this then chances are it wont cause a noticable upset to your insides when cooked+eaten as part of a meal.