I currently have 7 laying hens with a 7' long 2'x4' layed flat for the roost. There is a 1"x10"x7' a foot below it for the poop board. My question is that I have 6 new pullets that I am about to add to the perm coop. How much roost space do I need for 13 hens and any ideas for adding more roost space? Thanks.