Wow, now everyone has given me something to think about. Nikko absolutely adores greenies and he will chew away at it until it becomes this small green shapeless blob. I didn't know they were dangerous and I will stop giving them to him so often. He is teething and it was refreshing to see him chewing on something else other than my slippers.
And you say they are addictive too? I did notice Nikko acting a bit strange. He growled angrily at my fiancee while he was chewing on one. Apparently he thought my fiancee was going after his Greenie. He never acted like that before, and he chews rawhide all the time.