I just did a bunch of research on chlorophyll for dogs because my dog's vet prescribed a homemade herbal mixture containing chlorophyll drops for my dog. Apparently mulberry leaves are a rich in chlorophyll (along with alfalfa-which is somewhat controversial concerning safety for dogs), and one of the main reasons dogs love grazing in the grass is because grass is rich in chlorophyll. Chlorophyll has numerous health benefits for dogs and is actually considered somewhat vital for their health as it helps prevent cancer, aids in digestion, cleanses blood, detoxes all organs, etc. Unfortunately they can't sufficiently digest grass well enough to absorb a beneficial amount of chlorophyll from it-observe stools for evidence
So perhaps this is a big reason they are drawn to mulberry leaves too, and why your dogs nibble at them for 5+ minutes (to make it more absorbable for their bodies). Go figure
