Eating wood!

[Horsewmn@aol.com]

I have a 3 1/2 year old gelding that's eating wood like a beaver.  The rails,
tops of posts, downed trees, stumps, you name it.  He gets free feed
phosphorus, calcium, electrolytes (Ismine) and trace mineral salts.  I've
tried switching hay (1/2 grass, 1/2 alfalfa), he's on Dynamite vitamins.  I
have three older horses who are chewing more wood eating then usual, but not
NEARLY the extent that the 3 1/2 year old. Any one have any suggestions.  He's
not under fed (but acts like it sometimes and would probably eat himself to
death), he's not stalled (has 2 acres to hang out in), he's not lonely (he has
three other horses to play with).  Thanks for any suggestions. -Juliua