but this is still tinkering at the margins in genetic terms. "Visually, a Chihuahua is the chalk to a Great Dane’s cheese, yet they are still the same species, Canis lupus familiaris, and are direct descendants of the grey wolf. All domestic dog breeds are able to interbreed to give birth to reproductively viable offspring. This is because their genomes remain relatively unchanged, despite their physical characteristics appearing so different. This key evidence tells us that various dog breeds are not in the running to become a new species any time soon. It takes a long time for mutations, which cause inheritable changes to characteristics, to arise within populations." https://www.sciencefocus.com/nature/are-any-dog-breeds-close-to-becoming-a-new-speciesYes you are right that humans who like to eat meat often close their eyes for all the bad that is happening in factory farming.
And we didn’t have a discussion on broilers, but comparing them to layers was meant to give another perspective. A hen that lays 360 eggs in a year is twice to 4 times the amount , thats normal for most heritage breeds. This amount of eggs are largely not the result of better feed and housing. It has to do with changes within their genes too.
There are more examples likes this; A modern pig with 14 nipples is genetically not exactly the same as a pig 50 years ago who had only 10. Its like survival of the fittest solemnly for the benefits in the farming industry. Only use the descendants of the superb producers. Minor mutations, breeding and selecting by mankind are the cause of these (genetic) changes.
With dogs, cats and even chickens there are many more examples of genetic changes. People have been breeding on characteristic looks. In the past it was often functional, But today it’s more because we can or to win prizes. And too often the breeders went beyond the health and welfare of the breeds. Example: Some dogs like, Cavalier king spaniël and Maltezer suffer from headaches because of extreme breeding programs just for the looks.