Certain figures of veiled speech were used in Biblical times.
When ancient Israel first formed itself into a kingdom from a federation of lordships or judgeships, David was chosen (or elected) king.
There must have been official popular elections at the time. David was accused of sin for “numbering the people” [2 Samuel 24; 1 Chronicles 21]. It was obviously more than a census. There were “polls” at which people made decisions “with their head” to vote, and local health officials complaining about disease and epidemics, because they wanted to interrupt the free elections. That “Satan stood up against Israel” means only that there was an opposing political party, which necessitated a contentious popular election at official polling stations. The word “Satan” is Hebrew for opposition or adversary.
When people talked about “polls,” they were “using their head” in a popular sense of numbers, represented in an allegorical sense by the hairs on their head.
When David complained of enemies numbering “more than the hairs of mine head” [Psalms 40:12; 69:4], he likely meant that he was not doing well at the elections or polls. His son Absalom was not “conspiring against the kingdom” so much as campaigning for public office [2 Samuel 15]. The “haircut” or “poll” in the King James Bible [2 Samuel 14:26]. That was a real election or poll, not a haircut. Absalom might have been campaigning at barbershops or other public places where people congregate and converse, but the controversy in court was over Absalom’s political popularity and power of public office, certainly not the length or weight of the actual hair on any particular man’s head, which would be laughably absurd to make such a court battle or political struggle over.