Researchers at Tuft and Cornell have found that the vit K produced by our gut bacteria works to give bones their strength. Personal note: It is SUPER important for birds to eat raw produce, people! Because it is the raw produce that feeds the good bacteria in their guts which is essential for a strong immune system, digestion, nutrition, etc and now also bone strength!
https://now.tufts.edu/articles/vitamin- ... e-strength