I am sorry to hear of this strife and for their behavior toward you. I can hear how concerned you are for your young children. You are within your right as a parent that you ask your in laws to refrain from talking about this topic of hunting, or any topic that you deem inappropriate for your children. If they are unable to do so then you will need to think about how your visits with them go. It doesn't have to be contentious when you speak to them you can calmly let them know that is not what you want for your kids and you would appreciate that they respect your wishes around it. Talking to your wife calmly about it as well can help to get her on board. My hunch is that you will say they won't listen to your wishes and then you will be left with the decision about letting them spend time there and you and your wife will need to be on the same page about that.
I am here when you are available.
I am here again if you need. Be strong, talk with your wife and set the boundaries that feel right for both of you. Be well.