Yes. It is not common, but it is definitely not uncommon either. I have seen chucks w/incisors that had grown in a complete circle. These are not my photos, I have quite a few at home though. Mine were taken years ago w/my Nikon on 35 mm film and I have never scanned them. Funny thing is that the chucks did not look malnourished in the least. Me thinks it is because they are living in protein rich alfalfa fields and instead of eating one hour/day and sleeping 23 hours these defective ones are eating three hours/day and sleeping 21 hours.