We usually start 8-12 weeks out depending on how much conditioning the bird needs. Our cage sizes range from 4 sq ft (say for a bantam) to 18 sq ft ( 2 large fowl). Most are 6-8 sq ft. Sometimes we just separate into smaller coops/runs or tractors. Really just depends on the birds.
We prefer to use shavings for bedding. We get more breakage of feathers on our feather-footed breeds with wire and it's proven easier to clean. Once a week we go through with a tub, dustpan and brush and sweep them out. If I do it, I often do a quick sweep with the shopvac.
Each bird gets handled everyday even if only for a routine inspection. Birds being considered for showmanship get handled more.