This goes to the very heart of the liberal/conservative debate - and, as you can imagine, it’s not pretty. Our government says that you should cook a whole chicken until the temperature measured in the thigh is 180°F (82°C). If you cook chicken pieces, the government says, the thigh, wings, and drumsticks should be 180°F, while the breast should reach 170°F (77°C).
If everyone followed the government’s advice every time (along with basic sanitary procedures), it is virtually assured that no one would ever be plagued with the troublesome bacteria sometimes associated with chickens - and that are killed at 150°F (66°C). It is also virtually assured that no one would ever eat chicken again.
If you cook a whole chicken until the thigh reaches 180 °F, the breast will be around 170°F, and the whole thing will have turned to rubber. (And remember, if you don’t remove it from the oven until then, the temperature will continue to rise another 10 degrees or so while it rests, reaching the point of really, really tough rubber.)
Many recipe writers, cookbook authors, and food magazine editors try to skirt the issue by suggesting that if you know that your chicken is particularly fresh, hasn’t traveled far to market, or came from an area where bacterial contamination hasn’t been a problem, that you can get by cooking the bird to a lower temperature (as low as 150°F (66°C) in the breast). We think that approach is a lot of nonsense. In these days of mass production, there are very, very few people who know anything about the origin, handling, or travel habits of their chickens.
the same time, we have recently been reading Is It Safe To Eat?, by Ian Shaw, a professor and food scientist in New Zealand. He suggests lowering the risk of food-borne illness by handling food properly, but the thesis of his book is that, “the greatest risk of eating is getting run over on the way to buy your food, not from the food itself.”
If you follow our government’s advice, you’ll have absolutely safe, tough, dry chicken. If you handle chicken properly, but cook it to a lower temperature, you may be exposing yourself to a very slight risk of food poisoning, but eating consistently tasty chicken. We try never to roast a chicken beyond 160°F in the breast, but that’s our choice. You must make your own.
And, of course, the whole discussion is moot unless you have a reliable instant-read thermometer.