I've sprouted wheat from the feed store. For myself, I've bought a wide variety of seeds sold for sprouting from grocery stores and health food stores. There are places online, too. All you really need are seeds that are fresh and not treated with chemicals.
For just a few chickens, you could use any of the sprouting methods used for people sprouts. For a larger flock, then you get into the 5 gallon bucket method, where you use one bucket to contain the water on the bottom and one bucket that contains the seed on top, that's had holes drilled in it. You soak over night, then drain and rinse daily or a couple of times a day, until they're ready to feed.
For wheat grass, you can grow it the way they do for people. You can also just plant pots or flats of wheat for the chickens. When the grass is big enough, you can either cut it for them or just put the whole thing in the run for them. Or, you can just let your wheat sprouts in the sprouter get a little longer, until they start to get grassier.
I sprout more in the winter, when the garden and yard are buried in snow. I like alfalfa sprouts and eat them a lot. The chickens also love them. They also get wheat grass and love that. In the middle of winter, any sprout looks good to them. Chickens that haven't eaten sprouts before sometimes aren't sure what they are or if they are something that should be eaten. If you run into that, just sprinkle something they like on top at first.
