I think finding a stud owner you would trust to leave your girl with is the hardest part. I always visit before hand and look for a nice clean outside house, with adequate place for the queen, and a lovely friendly boy who doesn't mind you visiting with him. A stud owner who takes an interest in the likes and dislikes of your girl is a must too. Like SK said, regular updates, and the matings monitored initially to ensure the two are going to get on and neither is going to get injured.

I have my own boys for some of my girls, but they live in the house. Although I get enquiries about them all the time, I would never consider putting them at open stud unless I had the proper facilities. I don't think its right to bring an outside girl into your house where there is no real barrier between her and the rest of your household.