Unlike cats and dogs, all pigs are considered livestock (think about that word and what it means) and subject to legal requirements designed to prevent, identify and deal with outbreaks of disease. All pigs are at risk of getting highly contagious diseases which could a) affect pigs across the country (note: the authorities are concerned with the economic impact on pig farming rather than the pigs themselves) and b) in some cases be passed to humans. Whether the pigs live in your house or in fields, whether you have 1 little pig or lots of big pigs, you must register the 'land' they are on and get a County Parish Holding Number (CPH) within 30 days of their arrival. And you must also get a Herdmark Number which identifies that the pigs 'belong' to you (equally you must notify the authorities when you no longer have pigs). Both are free and easy to get hold of via a couple of phone calls, details can be found on the Government website here. (Please note requirements and the application process may vary between England, Scotland and Wales, so make sure you check out the guidance relating to your area). Without these numbers you can be fined. If 30 days have passed it is best to own up and get it sorted because you also cannot legally move pigs off your land without them. There is no reason not to get a CPH and Herdmark Number. As it can take time to get a CPH Number through, sort it out well in advance if you’re planning to get a pig at some point. Once you have that, you can apply for the Herdmark Number, the recommendation is about a week before the pig arrives but can be any time up to 30 days after.