i know this is going to sound silly, and agreeing with red's methods totally, and taking into considerations the warnings and that i think when someone says they always calm down, that's a little naive, but......
there are circles of awareness, tolerance etc and they are different for EVERY individual. when one "invades" these circles without the animals acceptance, they get agitated. and now for my always circular argument, i'm not saying don't go in there. charging means get away on my terms and means i need a little more space or respect, if not survival motivated, which of course since they "always" calm down, you never know what they have experienced. I think animals have a very good memory. if i put a hat on when i come home, my dogs think it's the neighbor and come barking, and then slink away in embarrassment and circle back for a pat.
before i used to buy, suggest, i made the seller "prove" they always calm down, which you may have done..
that said, and if your committed to the heifers and your time is limited, trust is number one. if you tie them up, find an approach angle which will not get them to express the behavior you don't like. then stay there and ignore them instead of creeping closer and pretending they are not annoyed by you. in horses, which will of course generate responses that cattle aren't horses, when they look at you and relax their mouth, they are relieving stress. this indicates more tolerance for you. when they tense up, use this as a guide to calm with what you have found works and enlarge that circle over their body to include the legs when you get to scratching. i actually lift up their feet as well on my heifers and rub all over them, take clippers out, turn them on, but not clip at this point. for the chargyness, i like to get a couple of people near them, just back from where they charge, and ignore them, getting closer on progressive days, finally scratching, ignoring, handfulls of feed etc till they look FORWARD to being near you. if you allow them to move somewhat as a gauge to how you are doing, rather than clamping down on them by tying tighter etc, it just takes longer for some that are this way. of course the easy ones don't need all this.
flightiness is the same thing if you have them on the halter. just let them move, when they stop, let them relax, with halter having slack and use the slack of the halter as a reward. these are usuallya little easier than the chargers, who seem to blow out their noses at everything, especially when you get to clipping on their face and stomping their feet.
an interesting thing about horses and movement. if when you are being a jerk and subconsciously not letting the horse go forward, right, left or backward, sometimes this is the reason they buck. also, interestingly, they will lay down, just like cattle do, when you are trying to halter break them and drag their face on the ground, kinda like a 4 year old going limp and saying stuff like i caaaaaaaaaaaan't. i just wait for them to get up rather than asking them to get up, or just go scratching on them right there.
for all this, i wouldn't let my kids do the above till you felt safe with them. do the above with several repetitions a day rather than long sessions once a day. and yes call the breeder and express reservations as a preinnoculation that you might want a further discussion. they should be interested in their progress if they want repeat business, because they don't "all" calm down.
Not to say people don't do it, but to give instructions......then you changed tracks (clapping)
