tdoro89 I'll dig up what I have regarding its history and let you know.
I don't know if I totally agree with your statement but do think it has some validity. But the decline is not due to hunting on Sunday's. If anything its the modern society and all that pulls a person away from church.
In regards to hunting impact on the number of folks in the pews on Sunday I would say it is minimal at best. The deep south seems to have no issue with it and Lord knows they're very rooted in their faith. Heck some churches have early services just for hunters. And if church is your thing there is always a later service.
Again though, this is not a religious issue. It's a property rights and personal choice matter.