I was an au pair to a German pastor's family in the late 1950s. He had 14 children between the ages of 2 and 28. And for some time he was a prisoner of war! There were only a few bedrooms, but beds were concealed everywhere, folding up into the walls, etc. Fetching the milk from the dairy (no doorstep deliveries) was a major chore in itself. No wonder they needed an au pair!
There was no hot water system and Saturday night was bath night for everyone; a huge geyser fed with wood hung over the bath and as you washed yourself you would throw a few sticks in to heat the water for the next customer. As you can imagine, the whole process took hours.

Sorry, I digressed a bit, but you brought back memories.
My husband's mother was one of 14 children and his father was one of 11 (no twins on either side). The next generation stuck to two per family!
Gillg