Number one - you are doing the right thing by moving your horses...and I agree about meeting with the vet before moving Lestat.
Number two - you are not responsible for anything else that happens at this barn. Period.
Why is the trainer behaving badly? Who knows? But - My guess would be that she is in a panic because the loss of your boarding income means the loss of her lifestyle. I mean, really...who the heck is going to come in as your replacement? Who is going to look at a barn in that condition and say "Sign me up!" ???
So that being the case...they are probably on the road to "out of business".
This is NOT your fault and you DO have to make decisions based upon the best interest of your horses...regardless of how it may be impacting the barn at this time.
Is the trainer taking it out on you? Sounds like it.
Would she really take it out on your horses?...Hopefully not - although she may be telling them bad things about you during the morning feeding (Your owner is such a b*tch! I don't see why she is making you move...)
Move as soon as you can...and in the meanwhile, try not to engage the trainer if you can avoid it. You don't owe her any explanations - nor do you owe the barn owner any extra chores or "favors". Be civil....and leave it at that.