I would suggest not doing the picture books; they are twaddle and, IMO, they take the spirit and soul out of the books. I think it is best to wait to read books at the appropriate time. The wait is worth it. You’ll face this decision over and over on whether to introduce books too early due to your own excitement to read it to them, but if you read them too early, they will either be uninterested or it could turn them off for future readings-and that’s bad.
As for the description of the pig slaughter: one of the wonderful things about her books are the detailed accounts of their lifestyle (one could almost do the same things based on her descriptions); it allows us insight into a way of life that is almost extinct, but was so vital to our country’s character early-on.
So in a nut-shell, put them aside and read all the great living books appropriate for their ages now – there are so many – and pick up Little House when they are around 9 and 7.
I second the audio books and the Pa’s Fiddle music that goes along with it, too.