What? I have been hunting for many years and never knew such stupid and unconstitutional law still existed. If I am reading you correctly, hunting is prohibited on Sundays in your state.

What is the basis of the state law? Religion? What else could it be?

Although I believe they (ACLU) are in many ways a despicable lot, the sportsman of your state need to run, not walk, to the nearest ACLU office. If your state has enacted any law that supports the views and wishes of any religious group, that is a constitutional violation of the required separation of church and state.

The prohibition is commonly referred to as the "Sunday Law." Many governmental bodies e.g., state county, city, etc, have had their butts kicked royally for legislating and enforcing a Sunday law.