BIG BIRD NESTS are made larger to accommodate birds that do not fit into conventional nests. Will accommodate large birds such as Jersey Giants, Wyandottes, Brahmas, Orpingtons, Rocks and large Rhode Island Reds. The 1 tier models come in 2, 3, 4 and 5 hole sizes. Current construction: galvanized side panels and perch brackets; plastic top, front & back partitions and perches. Front opening approximately 11" x 10". Sizes 2, 3, & 4 come with removable plastic nest bottoms while the 5 & 10 hole models come with metal bottoms. Nuts and bolts construction for the sizes 2, 3 & 4 hole Big Bird Nests. Need hand rivet gun for the the 5 & 10 hole Big Bird Nests. Shipped knocked down. Experts recommend 1 nest box per 4 laying hens. Big Bird nests are not convertible to roll-out nests.