My largest cage is 40 inches as a guess. Most of my birds are kept in very large dog crates. the biggest ones they make. The pair of rollers is in a large 30x30 inch rabbit hutch. All but the gaint house pigeons get free time outside when I can do it. I don't let the house pigeons out much because they try to take off, and go in the trees. Being they arerare, I won't want them lost. The archangle are better at behaving themselves and staying home. Flight time has to be supervised too because there are plenty cats here that would snatch them up, being that I live in town. Everyone is kept in pairs. The extra birds are caged seperate from my breeding pairs.