Thanks I was building a new pen I was hoping I had enough space to keep grass in the pen.

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Great idea! We are building our coop now, but we had to dig through rocky ground to burry the wire underneath to protect from the raccoons that we have been told a are a big threat in our area. I'm looking for ways to add gras to what is now, even before adding our chicks, a dirt pile in the run area.Have not tried these but here is a conversation about grass boxes
...and welcome to the world of chickens destroying grass! They'll eat ALMOST anything green. My enclosed run was initially grass/weeds. Within a month, it was dirt. You can not grow anything from seed in an area chickens frequent. They will eat the seeds before they even have a chance to sprout. I have since covered my dirt run with sand and it's much cleaner/easier to keep clean - and less muddy.
As for the grass... I discovered a way to grow fresh greens for my flock without them destroying the roots so it can re-grow. I made a box out of 2x4. I made a hinged lid for the box with 2x2 and stapled 1/2" x 1/2" hardware cloth to the underside. Something like this:
In the box I planted some winter rye grass seed that I sprouted in milk jugs in my garage. I chose winter rye grass 'cause it grows in the cold, and the grass will grow through the wire, unlike wide flat leaves like lettuces. Read about winter sowing here:
http://www.agardenforthehouse.com/2013/01/hows-your-winter-sowing-coming-along-2/
Hope this helps