I had 10 nest boxes for 32 hens, but since I have 3 banties that stay broody all year long, I found all of the boxes would be full at times. Recently I went into my barn and made about 5 more out of stored items like an oversized old rural mailbox, a 5 gallon bucket, an old water closet tank, and a rubbermaid storage container. Took them about a week but some are using them. Look up the threads on nest boxes and you will see all kinds of ideas.