Some good reason to not go on using things from animals

Animals with any nervous system should surely be given benefit of the doubt, any of them likely do feel things with awareness, so that should be with us leaving them alone. For all our nutrition to be the healthiest, which still allows for vitamin supplements, we would have it from plants. That is all I have been eating for over a dozen years, and nothing else but taking a little of vitamin supplements. These healthy ways I know of, that changing to would be good in any case, are with the great variety we should have, with being whole and not processed stuff that is used. It's all from just plants:
https://healthyaging.emory.edu/could-eating-30-plants-a-week-be-the-answer-to-better-health/
https://www.naturalon.com/10-nutrients-you-can-only-get-from-plants/view-all