Removing The Shoes and socks
Your best bet is to let the shoes get loose but get them removed before they fall off and there are a lot of reasons behind this philosphy. If the horse is lame before or after a shoe comes off get a professional trimmer in to check for major damage caused by shoes or their application.
If you want to make the change to barefoot and really want to plan ahead, you can try ringing one of the professional hoof trimmers wether they are in your area or not and telling them your plans. They will ask questions about how long the shoes have been on wether the shoes have clips and what happened when a shoe has come off in the past. The Rehab level guys will definately help to plan for the change over to barefoot.
DO NOT just take the shoes of and expect improvements, there was an old saying "take the shoes off and leave the socks on" IE: do not trim the hoof as it is undergoing changes from the shoes coming off. This is very bad for the hoof and the horse, you should have a professional trimmer come and show you the areas of concern on the hoof and explain what has to be trimmed and why. Rehab trimmers should be able to show you areas of muscle wasting or overdevelopment and describe how they will change and how long it will take.
I had the "socks left on" on a horse I own, at a barefoot clinic years ago and it showed how sometimes the only reason the horse is not dead lame is that the shoe can hold the foot together in weird ways. Once the shoes were off this horse with twisted feet the soft tissue was badly traumatised. The heel bulbs shifted above the plane of the pedal bone due to the shape of the hoof and the way the shoe was positioned.
IN ALL cases the foot MUST be shaped properly as soon as the shoe is removed and this may include a large amount of damaging hoof wall and badly grown excess sole must be removed. I have been doing this for many years and find the more accurate the first trim the faster the recovery time. The reason for the accelerated recovery is that the bones are aligned properly and the horses weight is born through those bones. If they are a little out of alignment the muscles and ligaments become involved in holding the horse up. One wrong mistep on these weakened structures can cause a strain and a temporary lameness.
In the case of my horse were the socks were left on the damage lasted over 6 months but the horse is perfectly fine now.
The first trim can be unusual and seem to go against the policy of natural hoof care. Unfortunately the damage done prior to the shoes coming off is cumulative and will get worse if the shape of the hoof is not restored immediately. On average if the hoof is trimmed accurately the moment the shoes come off the horses upper body recovers much much faster with less strain on the weak hoof capsule.
The main importance of the first trim is to re-align medio-lateral and anteria-posteria balance as if this is not adheared to the damage in the hoof can accellerate.
A horse that has had a long term Medio-Lateral balance problem will have remodelling to the pedal bone that without shoes will cause even more and faster bone remodelling.
There are many other problems related to the shoes and their postition and application. Half the problems are in the hoof caspule the other half are in the upper body. You can have nice looking feet but a very sore horse. With all of the new research going on, your best bet is to find a Rehab level trimmer that is well versed in massage techniques and Bio-Mechanics. Farriers may have have spent years attaching 80,000 sets of horse shoes but still not understand that a horse needs perfect balance to acheive top performance or how to read the horses body to find what needs trimming on the feet.
The feet on a horse may look good and healthy but the upper body is compensating for poor alignment. Remember alignment is needed to keep the horse healthy and performing, the feet can come second in the rehab phase. The outer hoof caspule may look good while the bone is destroyed internally by poor alignment.