most of ours started Nov 1st, then cats start Dec 1st.
I'm actually waiting until after Thanksgiving to start my line this year...so the waiting for "opener" is actually a self-inflicted one vs. regulatory. In the last few years, I've just had such a high percentage of unprime critters plus competing with upland bird and rifle deer seasons in first half of the month. Its much more fun to wait until after Thanksgiving for me and get some more solitude and quality returns on my efforts.
Of course, earlier also means generally milder weather, but I can deal with weather 99% of the time.
Jim-NE