Phil - one bad thing is over time having long hours does change the habits of these birds.

I have watched it change in 2 states now that went from daylight to noon to daylight to 3 pm to a half hr before sunrise to sunset. to a 5 day hunt to week long hunts back to back.

Gone are my scouting days of riding around in the truck and glassing fields. and seeing birds .
The birds just run now at the faint sound of any vehicle approaching - the sound and I am not kidding. I have witnessed it 1st hand many many times.
So I drive past fields that have held birds in the past and they are constantly empty. You might catch one running once and a while and it doesn't mean the population is down.
What you need is to change your tactics. May have to sit, wait, and watch more than drive around or glass areas from at a long long distance. Or go to scouting cams.
In all these years and people talk about honey holes. Well it is true, they are there, you just got to find them. Some areas are just a turkey magnet to which birds use year after year as long as the habitat does not change, i.e. logging, or no longer planted, etc.
One note I seem to find more sign in last yrs planted corn fields than bean fields. I key on cut corn fields a lot. And I walk more. I walk field edges looking for tracks.
I do have several areas I know I could go sit in today and get a crack at a good bird given I have enough time to wait them out.
So all day hunting will change things for you and you will need to learn them and then adapt.
Birds will loaf and sort of disappear around noon or on hot days. What they do is pick a shady spot and lay down or prene for a while. Birds will enter the field again to feed before fly up. find those feeding spots. that starts around 3 to 4 PM for me in MI and WI and will be later as the days get longer.
The last 5 minutes of daylight is my best time to get a shock gobble. I use in no particular order, duck calls, dog whistles, aerosol air horn, a gobble call, owl, crow, woodpecker calls or may a loud slap on a tree. I want to elicit a shock gobble. I do not use hen calls at that time. I want the tom to tell me where he is so I can get there in the morning. Or just go and sit one of my good spots for the day.
Hope I have helped but trust me you will see a change.

JW