The Chicken of Tomorrow (https://archive.org/details/Chickeno1948)is a video (film) from 1948 about how to "build a better chicken." It is 17 minutes long, so check it out when you have time.
The photo below is from the documentary Food Inc. (http://www.takepart.com/foodinc) and shows some of the progress achieved in breeding meat chickens since WWII.
Interesting to say the least. Thanks for posting.
Yeah, they have that movie on Netflix. Cool how you found the 48 clip.
https://www.netflix.com/title/70108783
Raising a Bigger Chicken, from the University of Alberta.
https://5minutiperlambiente.wordpress.com/tag/university-of-alberta-meat-control/