Very interesting, as always. Did those working-class parents in the Midwest include farmers, or farm workers? I had a picture book when I was a small child, given to me by someone with grown-up children so it went back a long time and had been published in the USA. It was set on a farm, and there were two horses named Clyde and Prince. That's all I remember, but the book could have appeared in the 1940s or even 1930s. Maybe a human name had passed into animal use? I only remember it because my family knew a Clive, and I guessed that Clyde was a misprint.