At the University of Minnesota at Madison Poultry Science Web Sight there are 100 year old adds from White Leghorn magazine advertising brood stock for sale out of 300 egg a year layers. Back then the chickens were the farm wives' responsibility. This was also before Rural Electrification had taken so much of the drudgery out of farm life and the miracle of electricity had made keeping large numbers of laying hens a paying proposition. But electricity made it possible for the first time in human history for the farm wife to keep large flocks of chickens and for the farm wife to financially benefit from large scale poultry farming by keeping light in the hen house for 14 or more hours a day during the Winter.
The egg industry back in the day was dominated by "egg brokers" who bought up eggs from the farm wife in times of plenty for a few cents a dozen and keep their speculation eggs in refrigerated warehouses in chilled brine, lime, water glass, or lard. Anything to block air, and bacteria to prevent or retard spoilage. Then around the Holidays most house wives cooked and baked with these 6-9 months old eggs because they were the only eggs available. Electricity, home refrigeration, and scientific chicken breeding changed all of this.
Please don't take my poor words for it, do your own research, and while you're at it draw every pint of water that your household and chickens use every day out of a well and tote this water for at least 100 yards, then do this every day for the next 30 days. I think before the month is out most of you will come-around to my way of thinking.
At any rate the slaughter age for most meat (aka) broiler chickens today is between 4 to 6 WEEKS, not months. This finishing weight before slaughter is 100% the result of superior genetics, breeding, food, and husbandry, but not a day of it is because of artificial hormones or chemicals in the feed. What ever your production goals are, they are your production goals and nothing else. We are all free to chose to produce as much or as little as our little hearts and pocket books will support. I hope that the new chicken keepers realize this and don't blindly follow the lead of people who don't share your goals. Believe me when I say that there is no correct way to feed chickens, only ways that are more productive or ways that are less productive.