As others have said, you can pick them up.
I attached handles to them because
*every so often, I lift them up to get debri off of them that the chickens kick up.
*after 3-4 months, I actually flip the frame over, let the chickens 'have at it', and then replant. I often do this if I will be...
You can make up your own from separate seed mixes.
But I buy bags of premixed seeds.
Look for 'Chicken Forage Mix', for example.
Here are some examples
https://www.groworganic.com/omega-3-chicken-forage-blend-irrigated.html...
I seed mine, then let them have at it as the sprouts grow. All I do is knock off leaves and the occasional poop now and then.
I use a mix of grasses and broadleaved greens and weeds; they chickens can get them all through 1/2" mesh once they reach the mesh.
They need to be reseeded about every...