It has been very hot here 105+, and I think I have been finding them all daily but it's possible they could be a couple days (they like to hide their eggs around the run). They are earing normal chicken food, whatever they find free ranging and all our veggie scraps.
We live next to a highway as well but our chickens have never attempted to cross it. The reason for that may be that we have a seasonal creek between our house and the road, but probably not because they go across all the time (and hide their eggs!!😠