My yards bigger than that! Plant more! See beagles above. Seriously, I can't imagine 1 acre supporting enough rabbits, deer, cotton rats, or anything else which could impact the shrubs that severely. Switch grass plot of that size is probably more useful as winter cover than nesting area anyway. Saw some study that indicated nesting success was a matter of acres per nest, rather than nests per acre, with quail it was between 2.5@ to 8@ per successful nest, and that was excellent habitat. I have not seen statistics for pheasants but suspect 75% of nesting occurs in alfalfa fields, as indicated by a Nebraska study, in the southern plains it's winter wheat. Switch makes good holding cover, brood cover, and emergency winter cover. At least that's the pitch by experts down here.