I think Patience's is barking because there is an intruder on her turf. She needs to be socialized to the horses in a slow but purposeful manner.

As for the barking....
MaxnPetey's mom has a similar problem with her dogs barking. Refer to "A couple of problems with our pack - long post" under the dog behavior section. While the dogs are barking for different situations, they may be barking for the same reasons.

This is part of a post I made in that topic:

The solution is to teach controlled barking through reward training.

Reward training is especially useful at defusing such situations as a knock on the door, greeting strangers, etc. According to statistics reward training has at least an 85% success rate.

Basically train your dog to speak on cue. This gives you a measure of control over the barking, which is, after all a normal dog behavior. If you put a behavior problem on cue, it becomes an obedience response. It gives you the control over when, and to what extent, your dog barks.

Not only do you teach the speak command but you also need to teach the Shush command. Always treat the desired behavior never reward the unwanted. Never punish the dog for barking. The opposite of reward is not punishment - it's no reward. Be consistent. Have someone over that can help you with the behavior in the house. Gradually working to outside. It takes time to unlearn a behavior so be patient and you should have success before you know it.

You can adapt this to the horse situation too! There was more posted from other people too. You may want to read over some of that advice. Good Luck in your endevor! It can be done.