well his heifers could have been calving, or maybe aborting which is common when they eat pine needles ( which is like cow candy) they get pine needle fever and abort their calves. Sometimes you can inject them with meds to stop the abort process sometimes it works and sometimes it does not. My understanding his herd were over 100 miles from his home and in rugged territory that would take a while. Adding cattle are easier to work and deal with at night they are calmer. But I do think it entered his mind to do his deed that night , but something stopped him. In calving season it is not uncommon to be up all night. Calves are your pay check. Fall is when most of them get pine needle fever according to my source.