Lack of vitamin K has also been attributed to coprophagia. I have a mare in my yard that has started this buffet diet and I am 99% sure it is associated with a long term antibiotic regimen that she just finished (Lyme). She is now getting SmartDigest to “put the good bugs back” into her system. Plenty of good info here in this thread : )
Sure there's right and wrong but mostly there's just a whole lotta different.