Ms. Piggle-Wiggle’s left her upside-down town house and has moved to a farm in the country. With the help of her cows and pigs and horses, she’s still curing girls and boys of their bad habits. So whatever the problem-from pet forgetter-itis to fraidycat-ness-the parents all exclaim, "Better call Mrs. Piggle-Wiggle!"
The first book, Mrs. Piggle-Wiggle (as well as the third, Mrs. Piggle-Wiggle's Farm) are very much about a parenting concept that I don't think even had a name back (1947-1957) when these were written. In the series' third book, Mrs. Piggle-Wiggle's Farm (1954), Mrs. Piggle-Wiggle sells her house in town and purchases a farm, where with the assistance of a large assortment of animals she continues to help children overcome their bad habits. In this collection, Mrs. Piggle-Wiggle uses no magic for her cures; the farm itself does the most good. In the fourth book, Hello, Mrs. Piggle-Wiggle (1957) she has apparently returned to her original neighborhood and to her magical cures. No mention of the farm is made for the rest of the series.
The Mrs. Piggle-Wiggle stories were based on bedtime stories Betty made up for her daughters, nephews, and nieces (and later grandchildren and grandnephews/-nieces).