This isn't going to end well.
Let's cut to the chase. Inviting bunnies into your home means you'll always be fighting a losing battle with hay to some degree. Hay has an uncanny ability to breed like rabbits. First it's a few stands now and then on the carpet. A little stuck on your shoe here, some hiding in your coat pocket there. Then it finds its way into the bedroom sheets. Or innocently appears in the washing machine. It'll catch a ride in your car. Maybe even make it to the office. Welcome to living with rabbits! We promise it's worth it.
Stage 5: Acceptance
Hay is to rabbits as gasoline is to cars (good luck finding a hybrid rabbit). Rabbits absolutely need high-fiber grass hay to keep their gut healthy and teeth worn down. Hay is their food - at least 80 percent of the diet - but it's also a source of fun and play. It's simply essential for healthy, happy bunnies. When you plan to adopt rabbits, plan on hay making its presence known at home, too.
A rabbit needs to eat hay throughout the day, not in small meals like we do. She should have a nice pile, about the size of her body, available for munching at all times. It's perfectly acceptable for a rabbit to play with her food, too. Encourage her hay consumption by offering some stuffed into toys and chews, sprinkling in some yummy herbs, or switching up the type or cut of hay every so often. Variety is the spice of life!
You probably notice your rabbit tends to redecorate her pen as soon as it's freshly cleaned and nicely arranged. The same goes for a nicely contained offering of fresh hay. She isn't trying to hurt your feelings. What looks like mess to us looks like home to them. The more time spent cleaning, the less time there is to spend with your rabbit. She'll put her things where she likes them anyway.
Here's what you came for
Just because you've opened your home to a new family member with a different idea of a good meal and a good time doesn't mean the barn look is your only option. If you have a house rabbit, you can can offer hay in a "pet store cage" or similar tray for easy access. She should be free to visit this spot as she comes and goes throughout the day. If space allows, offering multiple areas where hay is available helps rabbits eat as much as they should.
Hay mangers are another option to try and cut down on mess. These work well over a litter box. Rabbits are more likely to eat hay when it's nearby and easily accessible. They also will choose hay if it's presented to them when they feel like eating. Surprise - rabbits often tend to like to eat when using the litter box!
Whatever method you chose to feed, contain, and clean hay, a little mess will be inevitable. Take heart in knowing she enjoyed making it. It's okay to have a love/hate relationship with hay. Embracing the mess to some extent will allow extra time to simply enjoy your rabbit.
Oh, and a shop vac. That too.