1. Broiler — All chickens that are bred and raised specifically for meat production. The term “broiler” is mostly used for a young chicken, 6 to 10 weeks old, and is interchangeable and sometimes in conjunction with the term “fryer,” for example “broiler-fryer.”
2. Fryer — The USDA defines a fryer chicken as between 7 and 10 weeks old and weighing between 2 1/2 and 4 1/2 pounds when processed. A fryer chicken can be prepared in any manner. Most fast food restaurants use Fryer as a cooking manner.
3. Roaster — A roaster chicken is defined by the USDA as an older chicken, about 3 to 5 months old and weighing between 5 and 7 pounds. The roaster yields more meat per pound than a fryer and is usually roasted whole, but it can also be used in other preparations, like chicken cacciatore.
To sum up, Broilers, fryers, and roasters can generally be used interchangeably based on how much meat you think you’ll need. They are young chickens raised only for their meat, so they are fine to use for any preparation from poaching to roasting. Bear in mind: when cooking poultry, chefs know choosing the right bird will affect the outcome of a final dish.