Let me just balance comments so that you do not assume "all is rosy"
1. There is additional cost for regular hygiene
2. At times, sows die for no explained resason. Same for weaners. Once in a while, it happens also to boars (few boars in any farm)
3. Greatest headache is farm hands. Uncommitted farmhands can steal your materials for resale, lazily refuse to adequately feed or give water or even allow animals to fight to death etc, all for their personal gains.
4. There might be need for constant pen repairs because, pigs eat almost anything (including block work!)
5. God forbid African Swine Fever that can ravage the whole farm in weeks.
6. Lastly your start up running capital should be twice or trice your cost of start up animals - just to be able to maintain healthy feeding.

All I am saying is be prepared, for when any catastrophy or challenge face you in this business, the devil is a lier, forge ahead with determination. Afterall, I myself, did not allow anything to force me out.