Take a look at David Lancy's The Anthropology of Childhood; he describes in extensive, verging on exhaustive, detail precisely what you're saying. I just read it and wrote much more about the book here: http://jakeseliger.com/2015/03/05/thoughts-on-the-anthropolo....
I'd think they would get beaten first before being left out in the fields.
To quote wikipedia[0] on the matter:
> Until quite recently, children had very few rights in regard to protection from abuse by their parents, and still continue to do so in many parts of the world. Historically, fathers had virtually unlimited rights in regard to their children and how they chose to discipline them.
The Germanic myths around "elves" stealing children and replacing them with "changelings" often referred to as "oafs" seems to correlate with the behavior changes commonly seen around 3 years old in autistic children.
The myths that I've researched commonly described parents leaving their "changeling children" outside in the hopes that the elves would return their original children - but three year olds are not best known for their survival skills even when they're not autistic...