Transitioning 12 year old TB to barefoot

Q: I have a 12 year old thoroughbred gelding who has had shoes on since he started training at the age of 3.  He was an excellent dressage and eventing horse until he had an injury to the left front tendon two years ago. Recently, he has been unsound in several areas.  Some days, it's the left front, other days it's the left hind, etc.  So, I was advised to give him a minimum of 6 months pasture rest.  After being out for two weeks, he lost a shoe in the deep mud.  I decided after doing a little internet research, that pulling his shoes would be the best solution.  I figured that since the ground was so soft this time of year and he had room to roam, pain wouldn't be too big of a problem.  The owner of the pasture however, calls me every few days telling me that he is "dead lame" and can barely walk. She also says that when it's cold in the mornings, he shakes a bit.  It only gets down to about 30 degrees at night, which is why I’m wondering if that's what's making the pain worse.  The last time I went out to visit him, which was a day after I got the first call, he was galloping around with the rest of the herd and looked very happy.  I am concerned about the amount of pain he is in when I'm not around.  I would like to know how long to expect him to be in pain, how long does the average horse take to toughen up?"  Will he toughen up eventually?  If he doesn't seem to rehabilitate, do I put front shoes back on?  Do I give him bute in the meantime?  I am so clueless!!!  Any advice you have would be GREATLY appreciated. Thanks for your time.
 
A: There are some excellent websites with all the answers to your questions.  Which are good ones but ones that have a lot of "it depends" sort of answers.  Keep in mind that your horse's hooves are likely quite unhealthy and damaged from the years of shoeing, and especially from such a young age.  I feel for you in this time of transition.  The more you read and learn about the hoof, the more you'll understand why horses act the way they do when we ask them to be without shoes.  You would think they could simply "walk around on their own feet" and be fine, but the damaging effects of shoes over the years prevent them from even doing such simple things.  Do a quick internet search for "natural horse trim" or "barefoot horse" and all your answers are there.  I could write back and forth with you for weeks on end on this subject, but you'll pick it all up quicker by reading the good stuff out there.