Males would normally be castrated at a few days old, he is much to old to castrate now. If it was to happen it would need to be under anethsetic by a qualified vet.
I adour Tammys and if you think he is a good example to breed with then go for it. You will need to start thinking about separating him from the gilts now however. In the next few weeks he will start to mature, and before you know it he will be covering your gilts who could well come into season at the same time as he becomes active.
It would be a disaster for your gilts to become pregnant at a young age. It stunts their growth and they will never reach full size. It happened to us with one of our gilts. She had really healthy young, and she is a lovely pig, but she is small. The vet explained that she would never grow to full size but it would not affect the growth of her young. It does however mean that she will never have large litters because of her size.
If you do go the route of slaughering him, the same applies, you will still have to move him away from the gilts. You could then however keep him until 8/9 months and give him that extra growing time.
Let us know what you decided to do wont you.
Kate