I have 3 bantams (1) cochin hen, (1) cochin roo (1) silkie hen and then we have (1) barred rock hen. They range in ages of 4-5 months...how much more/longer will they grow?
All the breeds I've had have been mostly grown by 6 months or so, but continued filling out for several more months. As was mentioned already, large, heavy breeds tend to take a lot longer to grow/fill out. Technically, pullets are considered hens after they're a year old - same with cockerels-roosters.