re coping... the older siblings helped a lot with younger ones.
By age 12-14 the kids were working FT, bringing an income in or in the family business.
All the same sex kids shared a bed, younger kids might be in a mixed sex single bed with each other.
With so many on top of each other, their own body heat kept the place warm.
There wasn't spare food so no need for big space to store spare food in.
Each kid might have 3 outfits: something to sleep in that was extra layers in cold weather, day clothes, Sunday best. Maximum 2 prs of shoes each and shoes would be repaired & shared quite a bit. Little to store. Spare pants were a luxury. My step-grand-father in G.Depression had no shoes at times. Wasn't uncommon for kids to have no shoes.
Each kid might have 1 or 2 toys, often random small things; they literally got by with so little space because they had so few possessions.
I wonder about things like toilet training, toileting in general, trying to cook for a huge brood, in the sort of one room shack Dolly Parton & her 11 (?) siblings grew up in. Maybe someone has been to Dollywood & can comment on the practical aspects. People in tropical city slums have the same issues Now, lots of people in a small space.
Death... it was God's will and they were in a better place. People died all the time, it wasn't unusual for children to die.