During this retraining period, you may want to keep a leather crowned halter on your horse, even in the pasture. Generally I think it unsafe to leave a halter on a horse outside because I know of horses that have become entangled when trying to scratch an ear with a hind foot. I've also heard of a horse that hooked his halter on a gate latch and got hung up. Thankfully, it happened as people were standing there and was quickly released. Leather halters, or halters with breakaway crowns are safer if the horse becomes entangled.
If you want to be able to catch your horse you will have to convince it that being caught doesn’t always lead to discomfort or work. You’ll do this by spending time with your horse that doesn’t involve any of what it perceives as negative experiences.
Start by visiting in the pasture. Clean up manure, check for fences; anything but approach your horse. If your horse approaches you, don’t reach out and try to catch it. Just let it approach, perhaps sniff at you and then you walk away. Don’t let your horse walk away from you. You always want to be the final decision-maker in any exchange with your horse. Several brief visits a day will be more effective than the occasional long visit.
When trying to approach your horse don’t march up to it full of purpose and intent, it will read your body language and think ‘oh, oh, something is up’. Instead soften your body language, meander towards your horse. Don’t make direct eye contact. Don’t approach head or tail on. Use your peripheral vision and approach at the neck or shoulder.
If the horse allows you to get near enough to catch it spend a little time doing something enjoyable like scratching, massaging or brushing. Use your knowledge of what your horse likes. Again when you are done, don’t let your horse conclude the exchange. Decide when you are done, unhook the lead rope, make the horse stand, and walk away from the horse.
If your horse only runs away when it sees you coming with a halter and lead rope, then always approach it with a halter and lead over your shoulder. You have to teach your horse that the appearance of the halter and lead does not mean you are going to lead it in to work.
Bribing your horse with treats is only a short-term solution to your problem. Treating a horse, especially if there are other horses in the pasture can get dangerous. If the pasture herd learns that you always come out with treats in your pocket you could get hurt as they jostle each other to get the hand out. You want to be able to catch your horse without carrying out a bucket or a carrot.
If your horse will absolutely not allow you to get near enough to catch it, you’ll have to carve out some free, open-ended time and have your horse in a small paddock or yard. A round pen is too small and a large pasture will work only if you don’t mind walking for miles.
When you approach your horse and you know it will run away from you, keep it moving. Use a longe whip as an extension of your arm to cue the horse to move forward. The best gait is a smart trot. At the beginning your horse may act like this is fun —and gallop, buck and kick. Let him play and he will settle. He may try to stop. He may even try to approach you at some point. But don’t let the horse make those decisions. If the horse tries to stop tell it clearly and firmly to TROT.
Ask your horse to HALT—or whoa or whatever term you use consistently after you see that he is beginning to pay attention to you. He may start looking towards you, flicking his ears, or lowering his head. When he is working steadily around you at the trot that is the time to ask for a halt. When he does as you ask, praise him and send him on his way. Do this a few times so you know you are getting a consistent reaction to your command.
When you see that the horse is halting obediently on command, drop your whip and approach him. If the horse stands quietly praise, scratch or pat and walk away. Send him out at a trot again. Repeat the process until you know the horse will stand and wait for you.
Only after you know the horse will stand should you attempt to catch the horse. If he ducks away from you send him on his way and repeat the process. You need to convince him that standing to be caught is more comfortable than running away. (You are not trying to run him to exhaustion.)
If he does stand for you make sure there is a reward at the end of the lesson. Put a lead rope on him and lead him to a treat in a bucket, do a little grooming or massage. And then turn him loose in his pasture. The next time you have a moment visit him in the pasture or paddock. Let him learn that your appearance does not mean he has to go to work or suffer discomfort. Tip: Friendly horses in your paddocks might help you out. If they will walk up to you for pats and scratches, your hard to catch horse will see their behavior and may imitate them.
Jealousy can also help.....pet and play with another horse in the pasture, completely ignoring your horse until she comes up to you willingly. Then give her the same attention you were giving the other horse.