We recently lost about 45 chickens and roosters and four ducks. We have yet to identify the culprit but it can climb well, fit though tight spaces and is vicious. We suspect a weasel or raccoon. One night, after I had spent a couple of hours blocking every place I could think of, it got in and destroyed twelve two month old pullets and apparently removed 5 ! We want to start over with groups of 100 layers at a time and need information on how to build a predator proof room in the barn and a yard for each group. We do not kill our birds and prefer to grow them as close to organic as possible. If you know of plans or pointers we could get, please let us know. We do not feel the coop plans for sale on the web will fit the situation. Thank you, and happy fowling!