I happened to stumble accross a nest a couple of years ago. Literally would have stepped on the hen with one more step if she had not flushed and flew. If you think a pheasant or covey of quail will startle you......
Curosity was too much and I went back to spot a few days later to see if I could make her out. The nest was in tall grass beside a yucca bush (West Texas). I had the spot landmarked good and was amazed that I could not see her no matter how hard I looked even within 5 yards. I began to doubt that I had the right yucca bush and got too close and flushed her again. I felt bad in doing so and avoided the temptation to go back until way after incubation period. I found her cracked open eggs which made me feel good that I didn't force her to abandon her nest altogther.

I guess an elementary question but one I have always wondered about and never been certain is whether a hen ever stays on nest at night or does she always go to roost?