In that one room the parents had sex. Right besides their old folk and the children. Sometimes the old folk had energy to have sex too. And yes, the children were frequently awake and watching. That includes all of you great-great-great-...-great-grandparents, and all their ancestors.
Besides that, almost all children worked in animal husbandry, helping quite directly several species of domesticated animals to mate, from goats and sheep to cattle and horses. What they saw when doing that was no different from what they saw their parents and grandparents doing at night.
Do you really think parents were sharing intimate moments in-front of everyone? You don't think that they waited for the cover darkness and did it quietly or went off somewhere private to have that moment? Kids know what is happening. They don't have to see it to know. As you point out, they would have been exposed to animal husbandry. They didn't need to watch their parents or grandparents openly do it. I highly doubt that everyone was sitting around watching each other but you're welcome to your opinion.
The clash of ideas is the sound of freedom.
