Does my EBT have OCD?

My two-year-old English Bull Terrier has a habit of eating anything and everything in his way during his morning walk with his canine chums. As he passes bushes, trees etc he will grab at green/brown leaves, twigs, grass, thorns, plants, flowers and he will eat them. He will forage for and consume twigs, cones and even cigarette ends if we stand still to chat.
He is walked off lead and although he either stays with the group or goes off to meet a new friend, it seems his second favourite pastime after chase and being chased is this obsessive eating. In the afternoon he is walked off lead again in an equally edible environment, but on our own. This time he doesn't go around eating everything in sight whether he sees other dogs or not!
Is this a type of obsessive compulsive disorder? I will not muzzle him because his peculiar eating habit does not make him ill; neither do I want people to avoid him (being an EBT is a big enough trust issue).
My friends think it's hilarious and, apart from turning the forest into dessert, there are no other strange behaviours except for the well-documented "bully wind"!

Janis Conway, by email