I'm going to peeve a whole bunch of barn owners out there but I've really heard, read and experienced ENOUGH.
D O N ' T EVER give notice when you're moving your horse. It seems like lately everyone is using the notice for crazy stuff to keep people from their horses.
Make sure you are paid up on your horse board bill. Find a new place to take your horse(s) and pay for a stall as of a certain date. Hook up your trailer or hire a hauler to go pick up your horse.
Example: June 1, pay your board bill in full. Go find a new place and pay for a new stall starting June 15. Start taking your stuff home a couple items at the time so that you don't have a huge packing job on the day. On June 15 go pick up your horse. If the anyone asks where you're going you have 2 choices. Either tell them it's none of their business or make up that your horse is going to the vet or a show or on a trail ride. Move the horse, call the barn after you're gone and tell them you're not coming back. If they scream about 30 days notice, tell them you're giving them 2 weeks (since you already paid for the whole month) and tell 'em to sue you for the rest.
They won't bother, it's not worth the time and money. Even if they do, show up and argue why you shouldn't have to give notice and cite these crazy threads and stories about people who have given notice and had nothing but heartache because of it. They probably won't prevail.