This probably has been mentioned before but I will throw this your way. I read that you should not feed chickens or any live stock grass that has been cut because it can get caught in there throats or craw/crop, When they nibble on grasses they take just what they need and aren't at risk of choking? I'm sure I read this somewhere.
OleLady Said:
"Fresh grass when we mow and weeds out of the flowerbeds, flowers too. And any other thing that comes our way. Like the wild strawberries and termite swarms"
I think you need to make sure to chop or grind up weeds and grasses