OneDoxieMom...Some of the gourds do not have porches, yet, because I have not gotten "a round tuit" to get them all installed yet. The birds love the porches and tend to claim those gourds first.
There are several modifications I make to my gourds - the natural ones, and the man-made Super Gourds and/or the Extruder Gourds. I add 3" PVC tunnels and/or porches, put 3/4" plumbing elbows near the top of the gourds' necks for more ventilation to keep the nests and chicks dryer and cooler and add hanging tubes so rain cannot drip down the hanging wires and into the nests.
This photo shows a SuperGourd, like the one shown with the two martins, with the access cap removed. You can see my fingers reaching in through the tunnel and the little "step" at the bottom of the tunnel. It helps the young birds grip the tunnel to get out. The tunnels help prevent hawks and owls from reaching inside with one foot and dragging out the little martins. The cedar chips are the pre-nests I put in before the birds arrive.