I agree - when you notate every penny, people will be able to complain about certain pennies. "I can get hay cheaper than that" (of course it's carp hay). "I have coupons for grain" (many places don't take coupons - especially if you are buying in bulk). Just tell her the costs have gone up in the last few years and in refiguring your budget, you need to raise the board by XX dollars.
Don't give her room to argue or she'll play you. Throw your shoulders back and tell her she has X time to move out. It's your barn - you don't have to give a reason as long as you give a fair time notice. If she badgers you, shut it down by not engaging. Simply restate that she has to be out by X date.
People prove excellent points. But I still stand by that you should know what you and your sanity is worth. Good luck!
