Actually, they graze very nicely and make a nice lawn.
They eat the dandelions first... and a few other weeds... then wonderfully trim the grass.
I keep wondering if they remind me of cattle or horses..... because they eat a bit, sit and digest a bit, then repeat. I guess more horses
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Oh... as to containment.. a proper fence works. Have a goose herder is best... because then the herder can make sure the geese graze fir most if their feed.
The last time I had geese, I would have the kids herd... they herd easily because they insist on staying clumped together. Way more...