Like ponds and fish, figuring the amount of pasture needed per head is subject to the "it depends" rule. I don't know anything about your location, but it's common here to allow 2-3 acres per head for adequate grazing. Also like ponds and fish, if you are willing to supplement with additional,(read $$$) feed and/or hay, you can get by with less.
I have seen poor pastures, or areas in drought, where 4-5 acres per head wasn't enough. Don't be fooled by the spring flush of grass....conditions change throughout the year.
Maybe you could ask around in your area, to see what is the norm?
