Access to grass and greenery while keeping chickens safe from coyotes

[peter12345]

Hello: I could use your help please! We have had 6-9 chickens in Southern Cal and are fortunate to have a large yard. Our coop is 6x7 feet and the run is 8 x12 feet. While there are coyotes in the area, for 3+ years we could also let them roam in our backyard for much of the day within our 6 foot fence and there was not an issue until yesterday when a coyote jumped it quite easily and killed 3 of our girls. We would like the girls to still have some access to the yard but we need to keep them safe. We are thinking of making part of our yard (perhaps a 30 x 30 area) 'coyote proof' either by surrounding it with an 8 foot high fence or enclosing it with a 6 foot fence but with a covered top.

I have a couple questions:
1) What is the minimum area the girls would need to be happy and healthy?
2) suggestions on how to coyote proof our yard? Is an 8 foot high fence enough? I looked into "roll bars" but they seemed to have mixed reviews
3) Is it worth the time and expense to make sure the area they have access to is grass and other greenery (I would have to plant it)? If I planted it would they eventually destroy it?

Thanks!

Peter

 

[3KillerBs]

How about adding some hot wires to your existing fence?