Cat, most animals, and particularly penned animals, will have a smell attached to them. If pens and housing are kept clean most of us get used to it and don't " smell" it anymore. I can still remember the first time I walked into a cowshed and the really strong smell that seemed to be a combination of milk, crap and pee. Now I can't smell it. Pigs are the same but a dirty pig pen is something else again and there is no getting away from that smell - urine, faeces, old food and the musky smell of pigs are not a nice combination.
If your wanting to rear a couple of pigs for the freezer (and I assume this is what your looking at?), you have a couple of options. By far the best method is free-ranging them. It is far better for the pigs and can be of benefit to you - many use them to turn over their vegetable garden or break in new land. This can be simply done using electric fencing, either mains or battery, and fencing off an area large enough for the pigs to live in comfortably and this can be as large as the largest vegetable garden you will ever need
If you don't want them turning over the soil you can do the same thing but you will have to ring the pigs. There will be little or no smell doing it this way other than the normal piggy smell.
Or you can pen them. This is not my preferred option. You will have to provide a concrete pen large enough for the number of pigs you wish to keep and this is also going to require good drainage as the pen will need to be cleaned out at least once a day and rain drainage has to be taken into consideration. Pigs tend to grow better as they're not running around burning off energy but it's also a more labour intensive method and the pigs get very bored.
Housing can be basic but must be dry and draught free. Many of my pig houses in the past have been little more than little wooden huts with a door, a tin roof and either a limerock or wooden floor and filled with hay or straw. A nifty tip if living in a cooler climate is to build a frame the same size as the roof and attach chicken netting to it. Attach it to the house with hinges and in the winter fill it up with old hay or straw, lift it up so it sits against the roof and secure it in place. A cheap method of insulating the pig house and it works.
I hope this helps and maybe some other will come along with more ideas and tips.