I just went on a hunt for poultry feeds that contain zero animal products...I came across this in my search:
https://www.washingtonpost.com/news/wonk/wp/2015/04/29/consumers-love-chickens-that-are-vegetarian-fed-never-mind-what-the-birds-want-to-eat/?utm_term=.deae800fb2e3
I haven't found any...