Supplements and well managed diets do help, but of the available data, it looks like 12-35% are still deficient depending on area of the world. I checked for studies in USA and Europe. And of course, once that's determined for particular chicken who end up producing thin shell eggs - they get killed.
And ultimately, they've been bred to rely on said diet and supplementing. Vegans are against breeding as it is, let alone breeding them to be dependent.
Homie the problem with breeding them like this is selecting them to ovulate 300 times a year so we can steal their excretions.
Symbiotic relationships don't involve human breeding intervention. Least of all when it's for selecting traits that come to the animal's detriment. I'm not opposed to rescuing animals or providing accomodations for animals facing extinction so as to safetly raise young with minimimal human interaction.
You know what else isn't a partnership? Slitting their throats. Which happens to these chickens. Thats creepy. Assuming you aren't Vegan, which I don't think you identify as much, idk why you care if they go extinct - because you want to keep eating them? I just don't see good faith framing in your interpretation of what I said at all.