At first I attributed it to the lack of grass to chew on. Then it dawned on me- he's teething. I looked in his mouth and sure enough- there's an adult tooth coming in under one of his baby teeth. I get it. I really do- it must be driving him crazy. But he's eating every possible surface he can reach. Including, if you recall, Irish's blanket. That I've sort of solved by putting a ratty old blanket over top of his good one. I also spied a spray at the feed store to stop chewing. I bought it without blinking. As soon as I got home I went around the paddock spraying all of the chewed on posts. And I did Irish's blanket for good measure. I also sprayed the opening to his stall door, the door frame, etc etc. It seems work well. He sniffed and did the flehmen response.
Steele of course followed me around like a puppy. I introduced him to ice chewing- it used to work for the kids!