I have done some research recently on freeze marking, which is different from freeze branding. Freeze marking uses the angle symbols. The Arabian Registry said to contact Kryo Kinetics Assoc, Inc., located in Tuscon, AZ. Their phone # is 520-293-5448. I have not gotten around to it yet, but plan on freeze marking both our horses. If a horse which is not registered with a breed registry is freeze marked, a number will be assigned to it which is recorded with the company doing the marking along with all the other body markings unique to that horse. The freeze mark can be transferred with the horse if it's sold. As for pain, they say it does not hurt because they use liquid nitrogen which is extremely cold. I had my Arab mare freeze marked in the 80's and she did react, but I don't know if it was pain or just a sensation to the cold. Either way, it healed and the benefit far outweighed any pain, IMO.
As for micro chipping, what I have found is that there are 3 different chip manufacturers which have their own readers. Each company's reader can only read their own chip. So if your horse is chipped with ABC Company's chip and he's stolen and goes to an auction who is using XYZ Company's reader, it will not pick up the chip. As for pain on this one, they say it's no more painful that getting a shot.
Hopefully this will help someone out there!!