Sorry, I didn't see this post before. With Katie- Some horses start acting out if the bit you are using is too harsh. I would try using a softer bit or even a bitless bridle. You might also want to get Katie's teeth checked because a bit-even the softest one- could make her act up a lot if she has bad teeth. With the trotting problem- make sure you pick out her feet before and after riding. If this doesn't solve the problem, try doing some groundwork(like lounging) with her because (a) this should help strengthen the bond you have with her, so, if before the groundwork she didn't trust you enough to go fast, now she might trust you a little more. For Oreo-I'm a little confused on what you mean by 'he bolts a lot when I go in the pasture'. If you mean when you go to catch him- NEVER chase him. this will teach him that when you come out with that halter, he has to run. Try bringing a few treats out with you. Try a lot of different things. I will continue in the next comment....