We are new at this and we have a challenge: We would like to separate our backyard into 2 sections, hens & children. My question is how tall does the fence need to be? Do we need to block their view? We're afraid that if the hens can see us they'll fly on over, but we'd like to be able to see into the hen area (3-4 ft picket fence?). We'd hate to build a fence that doesn't work! We have no preditor issues thus far. Our variety pack includes: Aruacana, Leghorn, Black Star, Polish, & Wyandotte. Thanks!