Apparently there is an error with a chapter or two missing paragraphs after the previous updates. Hopefully this will be fixed soon.
The next ten chapters (21 - 30) of the Herds should also be up soon. Only ten to more to go and then back to Book 4.
Note for those following the Amity Series, The Heads probably should be read before Book 4. So don't worry if your reading both, it will probably make somethings in the next parts of book 4 more understandable.
Hopefully, if you haven't read 'The Herds' it shouldn't matter to much. You just won't know as much about Sable and Bron's history.