I have a rescue and they do carry baggage, mine was food aggressive(starved) and I learned the hard way to deal with her, but I won.You gotta have a lot of bravado, I went at her and raised my arms, cracked a lunging whip and made her move, I won. She still acts out but I stand my ground and tell her to fix it or turn and start walking, she wants her food or attention so complies. You need to be a little more agressive, I sweat when she rears or kicks but I react with a yell and charge, it trips them if they are used to folks running. But I agree with everyone, the folks at the rescue should be putting a new kid with easy's. Good luck and it's ok to run, just show a bit of attitude when you do it, you'll eventually get respect, horses are all about attitude,he who moves first loses, but stay safe too.
Many people have sighed for the 'good old days' and regretted the 'passing of the horse,' but today, when only those who like horses own them, it is a far better time for horses. ~C.W. Anderson