mixed ages of hens affect laying starts? how to find eggs in the woods

my oldest and youngest hens are 3-4 weeks apart in age. The older girls definitely have much redder wattles and combs, and both are wyandottes.

if they've started laying in the woods, how do I find the nests? there's quite the understory in the woods near our house, either ferns, sumac, etc. what's a woodland chicken nest look like? will they lay under the deck or under pine trees? I just don't see any eggs in waht look to me like nice places to go. But then I'm not a chicken ;-)

thanks