It's all about the tummy. If they don't sleep all night feed em cereal. Mom and formula sometimes isn't enough especially for a large baby.
My first was a very big boy, don't recall the exact stats but doc told us break out the cereal. It worked on all 3.
I've heard and know of several 3 child families and the 2nd is usually indeed the troubled one. I was very very fortunate that all 3 were trouble free. I told my wife if we had a girl first it would be an only child as I would not have a poor son with an older sister picking on him. She begged me for a girl after the first son and since I knew what causes that we had a daughter. The last one I think was an accident but definitely not a throw back. Keeper for sure.
My own family was per the rumor, my middle sister, both sisters younger than me, thank goodness or I probably wouldn't be here today was trouble. She turned out ok later and the youngest has had a few trouble making issues too but all better now as well.
Nothing serious, just kid stupid stuff. Stuff I'm just now thinking up and plotting with as I approach puberty.