Six weeks ago we got a pair of already bonded boars who were three months old, Peanut Butter and Nutella (1). After only two weeks one of them died suddenly (Nutella (1). We replaced him the following week with another boar of a similiar age Nutella (2), We kept them in separate cages in the same room for a week or so and initially let them see each other during cuddle time. After a health check for both of them the vet said it was okay to introduce them properly. We did this in on neutral ground and in a very large run. It went pretty well and they did all the noises and behaviour that I had read to expect. There was no fighting at all and they went back to a clean, disinfected and rearranged cage. This was about two weeks ago now and things seemed to be going fine. However, last weekend I made a tunnel run going up to a side level in the cage and just put a house and treats up there to encourage them up. At first only Peanut Butter would go up and down, usually just to eat the treats but Nutella (2) would not go near it. Two days ago we noticed that Nutella (2) had braved it and was now also going up and down using the tunnel. By yesterday though this seemed to have led to problems. I noticed that Peanut Butter was blocking the entrance / exit to the tunnel so that poor Nutella (2) was having to live up there. If Nutella (2) tried to come down the tunnel Peanut Butter would puff himself up and block his way. If he did get past he would chase him and generally bully him. I put water, food, hay etc. up there for the day yesterday and have made sure he is getting his share of food. Last night I took away the tunnel completely so they were both on one level. This lead them to go right back to the introductions behaviour but much worse than before. Although I did not actually expect them to fully fight I did at one stage get a towel out. I slept next to the cage all night to listen for a fight. There was lots and lots of chasing and chattering. I was very worried about leaving them today while I am at work and am desperate to get home. I did not want to rush and separate them too soon and undo what bonding (if any) they have done so far. I know this behaviour is to be expected but as a new Pig owner I am worried I will make the wrong decision. Tomorrow when we put them in the run to clean the cage etc. I was going to put in a second tunnel to the other side ramp so when they go back to the cage they have a 'side' each. Can anyone give me some advice PLEASE?