Flaboy,
Sounds like you're having fun. I've got my hands full here right now too, as I'm currently starting two four year olds that I picked up (one is a big time over reactive kind of horse that loves to buck when saddled - so we've got a few kinks to get worked out yet before I step up on him), a five year old big grulla mare that I'm fine tuning for sale, and a two year old stud prospect that I'm laying the foundations on.
Anyway, not much of an expert with the round pen, but basically here's how I understand it to work.
In theory it's effective because you use pressure and the release of pressure as a reward, much the same as horses do to each other when showing dominance.
When you introduce two horses to each other in a pen, the dominant horse through body language (and sometimes a few well timed nips or kicks) will herd the less dominant horse around the pen.
When he feels that the less dominant horse understands the pecking order, he will back off the chase and ignore it.
So what I do is use pressure (as in me getting into the horse's 'comfort zone') to move the horse around and exert my dominance. This includes making the horse change direction by blocking their forward motion and increasing pressure to speed them up.
And don't give them a break until they start submitting, which sometimes is as subtle as nodding the head or licking the lips as they're circling.
With some horses that are fairly strong minded this can take quite a few laps - usually they'll exhibit signs that they don't want to submit such as keeping their face turned away from you as they circle or turning their hind ends towards you.
You'll know you're winning when the head starts turning into you and the horse begins to keep an ear turned in your direction - big sign as he's now prepared to at least take your position seriously.
The reward part is when you take the pressure off, so for example, say I'm round penning a saddle horse that's become a real dinkus to catch.
I'll make him do some laps until I can see that he's nodding or licking his lips, and then I'll say "whoa" in a clear firm voice, and then I'll step away from him and turn my back to him.
This in effect takes the pressure off of him, and it's amazing how quickly they'll pick up on it. They usually need this repeated a couple of times, and next thing you know when you say "whoa" that horse will stop.
Some folks like the horse to 'join up' with them (approach them once the pressure is taken away), but personally I like them to stay put once I give the 'whoa' command.
If the horse starts to move away before I 'ask' him to, then I'll put the pressure back on him and keep him moving and changing directions until he shows signs again that he's submitting.
Once he's got the 'whoa' down pat, I'll start by slowly walking up to him a few steps at a time and repeating the 'whoa' command. If he stays put, then I'll eventually work my way up to him until I'm close enough to give him a few rubs on the neck, repeating the command.
If he moves off at any time without being asked, it's back to some more laps again. If you keep at it, eventually he'll understand that it's less work for him to 'whoa' than it is to make laps.
It's amazing how well this works, as every horse that I've done this with will let me walk up to them and catch them in a big pasture even though they're with twenty other horses, even though they've been worked hard the day before.
Basically, you use the pen as a tool to punish improper behaviour by making the horse work, and reward good behaviour by letting the horse rest. It's even great for hard to bridle horses - if the horse doesn't let me put the bridle on, then he sweats. He stands nicley and get bridled and he rests.
Anyway, this is just sort of how I'm muddling through. So far it's working, but I'm looking forward to hearing how other folks utilze their penning techniques.
Sorry, just looking over what I wrote and it kind of ended up long winded.
Take care and have fun with your colts.
