Well your heart is in the right place and you sound like you are trying to do the right thing and getting all your ducks in a row before the mini raffle but, like the others I too feel like there are other ways to raise some money.
You didnt mention this but is this for dogs and cats as well as horses. Is it the local town Humane Society or is this a privatley run facility. Most of the ideas are not going to be a quick, dollar in the pocket type of ideas, these will take a little planning and hopefully if you bring awareness to the cause your group can get lots of volunteers to help.
If you can get businesses involved...they are the ones to get you the big donations.
If you have a local carpenter/builder have them build say 10 lg and 10 sm wooden dog houses...just the simpliest design...your plain old typical roof,sides and door ( maybe you can get Home depot or the like to donate the wood )Now find your friendliest spokesperson and have them go to businesses and sponser a dog house that they can decorate and be as elaborate ( paint, wallpaper,add porches, what ever ) or simple as they would like. Often they will decorate it to look like their own business AND it gets their employees envolved ( which can mean more $$ too )Charge what ever you think, maybe 150.00 for the lg and 100.00 for the small. You must get everyone in your local town to want to be a part of " Saving the Animals "and you want them all to want to get a house to decorate ( its an ego thing, but who cares LOL )Get local paper involved and see if they will run a little story about what you are doing to raise $$. Your goal is to have interior decorators, fabric stores, tack stores just anyone that is willing to really come up with some neat dog houses that you auction off later at your big gala event( they must be safe usable houses.... maybe a big Dinner in the Dirt ( simple spagetti dinner w/salad and maybe garlic bread is cheap and easy ) or Pies in the Paddock ( Pie Sale where people make lots of pies to donate them to sell) where you obviously set this up in a pasture or someones farm. Local school children to decorate the tables with lots of framed photos of some of the animals in need, photos of the shelter showing improvements needed, include tear jerker photos and success stories. Maybe put a small pen up and sell squares like they do in a foot ball pool as to where the mini will make a mini muffin...like they do with the cows.At this same event while having dinner you could have people watch a fashion show of local rescue dogs and horses...yes, just lead them right through the tables but leave plenty of room for animals to walk. Use photos of animals in need and paste on colored paper mabe add a magnet and put some facts about the animal on the back, hang them on a tree or fence and ask people to pick a pet they would like to help maybe 2.00 and bring their favorite to the cashier they get a magnet and you get more $$. You may be able to set a fake tree or fence post up in a local tack shop and just keep adding photos every week. Have children write a story about why everyone needs to take care of their pets. Have them read their story out loud at your event...all kids have parents, grandparents, aunts and they will want to help too...this means more money.
Martys idea about having local bands perform is great. I also love the idea of getting bikers involved...Harleys for Horses or Kawasakis for Kitties..maybe get people to bring their fancy bikes and set up a little photos shoot with photos of the donors sitting on the fancy bikes. A couple $$ per picture.
These are things that do take some planning and in order to really raise the big bucks you HAVE TO START EARLY and Talk Talk Talk about it. Make people think that this is the gala of all galas but make it more like Denim for Dreams....just a real casual thing but with a great cause!!
As Im rambling I just thought of something else fun but maybe a little over the top...too much. How about a Trailer Trash-ing. Sell buckets of clean horse poop and let people take out frustrations on a donated horse trailer. You must promise to clean this idea up really well once you have finished.
O.K. Im getting alittle off base. I'll stop now.
Bake sales ( Im a major foodie and will pay big bucks for homemade pies )and car or horse trailer washes are very easy to do for quick money.
If you have your heart set on a raffle I would go with the idea of a pony for the day idea or just a day at the barn idea. Good luck
P.S. I love the goat idea but I think they should have used a big ole piggie!!