My new filly needs to have a stud chain on when being led. And Im just asking, how do you atach it? I've seen it being attached at the top buckle and then brought over the nose, and I've seen it on the buckle closest to the mouth then brought over the nose, over the gums, under the jaw, and I'm confused! LOL please help!
I do not use a stud chain on my stud except in halter class - I use a rope halter - they are very effective. Have you tried rope halters?
What makes you say that you need a chain on her (did someone tell you this, or is she really pushy with you?). Usually some additional groundwork activities will really fine tune respect and responsiveness from the ground and remove the need for harsh tools. There are some great videos and books out there that can help you with the ground work. You could also look into trainers in your area to get a quick lesson or two (that is all it would take, and a few minutes a day for a while).
I agree that chains can create headshy horses. How old is your filly?
To answer your question, basically all of the ways you described (and more) can be used with a stud chain - it depends on your preference and what you are trying to accomplish, as well as what seems to work best with the horse. In halter, my chain goes in one side ring, over the nose, through the other side ring, and hooks to the higher ring on that side. It is different for mares and geldings though.
Can I ask why you believe that young horses "need" a chain? You ask how to use one but you say she needs one why? If you can't use a rope halter to fix whatever you are trying to do then change the why you train don't go harsher, that would make it worst. I use nothing but rope halters all the time, never know when you might need to do some ground work.
Have you tried leading her with a rope halter rather than a chain yet? What does she do?
If you use a rope halter in your ground work, shouldn't these skills carry over to when you are leading her? Parelli, and other trainers have some great activities that you can practice in your ground work, and add to your "bag of tricks", so that you have ways to handle your horse, when she gets excited when being led in public. Rope halters are cool too because they can double as "natural hackamores" :)
This is the halter that I use for leading at home and in public places for my boy. He is four in this picture. Just one of your options...
If you train your young horse properly in a chain, I know that it can be done effectively so that the chain can later be removed when the horse has the leading skills (I know this has been done with some halter horses).
Choose what works for you, but know there are other options out there :)