Most of their diet is satisfied by grazing. They are excellent lawnmowers. I don't even mow my backyard anymore. My ducks,geese, and chickens pretty much keep it mowed for me. I keep feed in their pen and they can eat as they feel like it. Sebs are not very successful at breeding due to their curly feathers. That is why they are so expensive. They need deep water, not just the smaller kiddie pool. I have a pond, so it's not a problem. They mainly mate on the water. They are beautiful. I love looking out back and seeing the wind blowing through their feathers. I only have two now, a male and a female. I hope to have more this spring during mating season. I just sold off the last of my babies a month ago. My goose laid an egg this week and it's not even laying season. I'm thinking she may be lonely without the babies. They are very family oriented. The babies were a year and weren't even hers, but they all went everywhere as a family.
Hope some of this information helps you. Good luck on your adventure to find some.