good book
There is a book by Donald Zochert called Laura: The Life of Laura Ingalls Wilder. It fills in the blanks of her books and explains the difference between her books and her real life. She basically adapted her life stories to make them more enjoyable for children to read. That's why she omitted the parts where Pa was hurting for work and the baby boy that died. It also talks about the search for the site of the actual little house on the prairie. By the way, Laura's stories from the Big Woods were from when they moved from the prairie back to the Big Woods. She was too small to remember the move from the Big Woods to the prairie.
My two cents: They probably changed the breed of Jack b/c Australian shepards are much more easily trained than bull dogs. And they're prettier.