I have 3 sows that all get along well, and i just purchased a boar. I put him in the pen with them and they attacked him and would not let him be. I put a partition in the pen where they can sniff each other, to maybe get used to him. The place where I purchased the boar from, the sows and boar were kept together all the time. Someone told me I should not put them together until they are in heat. Any advice?