I'm hoping to build a chicken tractor coop that can hold about 5 hens. I would like some input on how big to make it and keep the chickens safe from predators. I plan on putting the chickens in the tractor coop during the day and putting them back into the permanent coop at night. Our main predators in my area are: bears (though mostly at night), coyotes, cats (mountain lions, cougars, etc.), and hawks. Advice is much appreciated.