My chicken cookbook is 30 years old, but chickens are larger now. How do I adjust the recipes?

According to this marketwatch article (https://www.marketwatch.com/story/why-chickens-are-twice-as-big-today-as-they-were-60-years-ago-2017-01-06), a chicken 30 years ago weighed about 4 lbs. A chicken today weighs about 6 lbs. today, a chicken breast weighs between 0.5 to 0.75 lbs (8 to 12 oz), which is a 6th to 4th to of the total weight. Now, the breasts likely increased at a higher rate than the rest of the chicken over time, but we could estimate that the chicken breast of the 1980s weighs about 5 or 6 oz. That is 20 to 24 oz of chicken breasts, or around 2 to 3 chicken breasts of today.