My horse is eating everything

I have a 4 YO old QH. About two months ago she started chewing the bark off the tree's. I have tried to entertain her other ways but she prefers to eat wood. I also tried a cribbing collar and that did nothing. She has a salt block. She also ate the cedar door of my chicken coop letting them all out. Is she bored or what?

Many horses chew wood for one reason - boredom. My horses never chew my fences until winter. That is because all summer long they have grass to graze, but once winter comes they continue to be well fed, but it is hay only twice a day and they end up with quite a bit of spare time on their hands. Horses were created to graze 24/7 and if they aren't actively eating, they will find something else to do to fill their time, and that thing often involves chewing.

And yes, your horse is at somewhat higher risk of colicing if he chews and eats alot of wood.

First, is there any way this horse could get into a pasture situation? (I'm assuming she's in a paddock or a small pen since you mentioned feeding hay and cubes) If possible allow her to graze most of the day. Also, ideally have her with another horse for a companion, that also is a good way for them to occupy time. I suspect some if not all of your chewing problems will disappear if she can graze all the time. If you cannot provide pasture for whatever reason, they you are going to want to keep low calorie hay in front of her as much as possible so she can be busy eating. Try clean but low calorie hay such as slough grass hay for her main feed, if you want you can suppliment her twice a day with a tiny amount of alfalfa hay. Also, you may have success with using straw for bedding instead of shavings, many horses will pick at the straw and eat it, which certainly is cheaper, easier on fences and their stomachs than chewing wood.