Here in Iowa I have killed several birds from noon until dark. The most productive time period for me has been from 4PM until 7PM. I never sit near the roost however. During this time I sit along field edges, getting to my setup around 3PM. Gobblers are used to finding hens again in the late afternoon/early evening in these areas as the hens come out to feed. I have found that in the hours from noon to 3, if I get a bird to gobble, it will come in. I usually leave this time frame for napping and I call whenever I awake from my light slumber and I don't sit where I anticipate them to be during that 4 to 7 time period.