Welcome to BYC duck forum!
If you are interested in learning more about ducks, check out the "sticky" section on the top of the forum home page. It has TONS of info on ducks and duck care.
Yes, they are messy. But if you manage it properly, it becomes pretty easy to care for them. They are fun, funny, cute and loaded with personality. Duck ownership is not for everyone. They are not just animals you can throw in a pen and forget, they need as much care as any pet, although it is a different type of care.
They can eat insects. They are great at keeping properties bug population down. But they also need a balanced diet of good quality, fresh pellets. I also feed chopped veggies, peas (as a treat), and I add cracked corn in winter. I do that because I am in a cold area. And, of course, they need water, and lots of it, clean and fresh too.
They need a predator proof area, and that is an area that you don't want to skimp on.
So, do some homework and reading and come to the wonderful world of duck parenting!!!!!!!!!!!!!!!!!!!!!!!!!!!