In South America marry gold flowers or petals by the ton once was and I think still are added to commercial chicken feed to create dark yellows and an enhanced flavor.
Is this healthier? I doubt it.
They do here in the US, too... They're famous for their "golden" skinned broilers and their "rich" orange yolks, all due to marigolds...
https://www.perdue.com
Oh and the article from the 90s I remembered and found it... No pictures though; can't remember where I saw the pictures lol..
http://articles.baltimoresun.com/19...28_1_errol-morris-chicken-meat-moral-judgment