Plants for chickens

Hi, I'm hopefully going to be getting my chickens in the next few months. I'm planning to get ex-bats and put them in my back yard for a while then probably move them to the allotment at some point so they can have more space. I have a few raised beds outside which are pretty empty at the moment (just some roses and a pear tree) so I thought now might be a good time to plant something the chicks would have fun with. I'm thinking something simple, where I can more or less just chuck some seeds in the soil and ignore them, and I'm fully aware that they'll get destroyed pretty quickly. Would plain grass seed work? Or something similar?

Grass seed will work. You could try sowing seeds for fat hen and other weeds. Try googling wild plants for hens.