Hi all, can't tell if it's a good idea to fly pigs in lower deck but depending on origin and destination of the consignment u may check with any cargo agent who will offer you a rate for 3 main deck positions with any cargo airline.
Flying pigs on cargo aircraft is no problem, CV recently had a few intercontinental charters full of pigs and the operation was carried out hands down. IATA AVI regulations determin how many pigs can be loaded in a container depending on the shoulder height of the animal. If that rule is followed there will be no problem at all. On modern aircraft such as the 744F the cargo hold carrying the animals can be kept at around 18°C in order to prevent the animals from catching a cold. Just keep in mind that pigs are easily subject to heart attacks and must therefore be handled & transported smoothly and carefully.
cheers