We are new to chickens. Had them for 4 weeks. They are 21weeks old, Red sex links. What are some signs they are going to lay soon. We know the combs get red, they have gotten very red recently. What about any certain behaviors to look for? We noticed a couple fluffy up neck a little and shaking head while walking through the run the other day and laying in a small hole they scratched out. Didnt know if thats signs or we need to keep eye on it for something else.