I'm about to triple the size of my secure run. Currently my birds have 55 sq ft, which mostly seemed like enough until several went broody and we added chicks to the mix. Now the chicks are 7 weeks old and the run is just TOO FULL. Most of the chicks are going away on Friday (assuming I can catch them; man broody-raised chicks are WILD*) but I'm sure this will come up again in the future.
So I'm going to expand to 143 sq ft, with a pen that can be divided into 3 areas as needed, which will make the introduction of new birds easier and will also allow me to pen off any of the birds that need a time out from the others for any reason.
*I'm going to attempt to grab them at night and put them in a crate for pick up on Friday. Keep your fingers crossed for me.