In my homebrew dragons are creatures of magic, hybrid beings of both the mortal and spiritual world. When a dragon kills and eats a deer (or anything else) it's not the gross physical matter the dragon needs, it's the spiritual essence that really feeds it. This is why some dragons hunt while others prefer to have sacrifices delivered to them and others can sustain themselves on more esoteric things like pearls or music. A dragon that eats sheet music is an annoyance, one that prefers virginal maidens is a menace. -Q.