Re: how many head
It all depends on your location. Here on my pastures in Iowa I need about 4 acres per cow/calf pair, But there are places in Texas you need 60 acres or more per pair, and then there are places in the bayou where you need about 1 acre per pair. You should find a local cow hand who can give you a little help. I think you will be surprised at the amount of space needed for 20 head and a bull.