I scraped up big chunks of grass and weeds -- we have it growing around her in the cracks of the pavement, or the corners of the yard. They love dandilion greens, and clover too. They like the dirt too -- and it keeps the grass fresher if it has the roots . . . you'll be amazed at how quickly they eat down a huge chunk of grass!
You must live close to me -- I think we are the only part of the US that is having a rainy cool spring / summer . . . I'm trying to be patient and thankful that we don't have 115 degrees outside, but it is hard when you only get 1 nice day, and then it gets progressively rainier again.
That parrot toy idea is a great one -- there's always a few goslings that can't stop with the chewing -- even my ones outside that are being raised by their parents have moments where they cant stop nibbling on each other.