The phrase "boiling bones" is a figure of speech used to describe a hectic or busy situation. It implies that things are very intense or fast-paced, similar to when water boils vigorously. Full definition
Bone broth — the rich liquid that results from boiling the bones of organic, grass - fed beef or poultry for hours — comes packed with a number of nutrients, including collagen. (mindbodygreen.com)
The cheapest, but least convenient, way to get collagen is from bone broth, made by boiling bones from grass - fed animals. (mindbodygreen.com)
As the name would imply, it's made from boiling bones for a period of several hours — possibly even days — until a broth is formed. (liveinthenow.com)