Chicken – Why stuff a roast chicken with lemon, onion, and thyme

I would suggest not roasting a chicken at such a low heat for so long. Here is a response to a similar question on another cooking forum:

A few days ago I printed out a recipe from peacefulnightdove "BEST Slow-Roasted Chicken". It sounded wonderful but was to be roasted at 250 F (126 C) degrees for 5 hours. That sounded like a low temperature to me, so I emailed the County Nutritionist and Health Agent where I lived. Here is her reply: Good for you JoAnn to be suspicious! That is definitely outside the USDA guidelines, and yes bacteria may well be growing for quite a while in there. Poultry especially should not be done at less than 325 degrees. You could use the same spices and onions, increase the temp to 325 and decrease the time. Figure about 20 min per pound for the time. The safest way is to use a meat thermometer, final temp in the thigh should be 180 degrees. http://community.tasteofhome.com/forums/t/173823.aspx

I would also suggest using a crockpot.

I suspect you may have created a poor-man's slow-cooking environment in there. You had meat, and liquid, and a median temperature of around 200° F, and you probably also got the bird close to "done" during the first broil, before you even left the house. This is obviously easier to do when the meat is covered (was it in a covered roasting pan?) due to the steam, but the oven does provide some insulation to begin with.

Technically when slow-cooking you should theoretically be able to speed up the process by quickly bringing the meat up to just below doneness/moisture-loss temperature (130° F) and then switching to a moisture-preserving slow-cook method like braising. I think that's what you accidentally did, but it's hard to say for because nobody was there for an hour and it sounds like you didn't check the temperature before the second round in the oven.

My guess is that the second roast at 400° F was probably unnecessary, and that the bird was already done, having been cooked in a very slow roast.

I'm pretty sure it wasn't the basting that helped. It seems to be regarded as a myth these days that basting keeps the meat moist, because the baste really doesn't penetrate the skin (and it's not the skin you're worried about). Basting is done to add flavour, not preserve moisture.

The recipe itself also doesn't strike me as anything special in terms of keeping the bird moist, aside from having a relatively short cooking time (as with any grilling/broiling) and letting the meat rest afterward, neither of which really apply in your case. It was probably the slow heat that did it.