My dog loves greenies too, however; he developed an alergy to all grains except rice. As I tried desperately to try a substitute for his beloved grennies I noticed the Denta Greens are made with rice flour instead of wheat gluten. This may be why they are cheaper and last a shorter time (rice is cheaper than wheat and a flour is looser than a gluten) but Max loves them just the same. The only qualm I have is the lack in size variety. The small size is more than I would like to give my dog since I have to constantly watch is weight. Needless to say we are happy to at least have an alternative to his greenies. :D