You can definitely hire several freelancers for the same job. You will be sending separate job offers to each of them and will have separate contracts though. If you plan to hire multiple freelancers make sure NOT to check the box "Close the job post if the freelancer accepts this offer ."
Jay, it is often very silly to only hire one contractor.
If you moved to a new town, would you go to eat out at only one restaurant?
What if the first restaurant you picked wasn't the best? Wouldn't you want to consider options? Even if you like to go to one place on a regular basis, how do you know the place across the street isn't a better value, and more to your liking?
I routinely hire multiple contractors to do the same design job. I mix and match what they provide, taking the best from every submission. I paid for all the work, so it's mine to do with as I wish... To use, toss, or repurpose.