These piggy banks are from Thüringen and where produced in de 1920's. They were used as genuine piggy banks, but even more often to put them in a collection in the showcases of the middle and upper classes in those years. All of them are green glazed (not the pigs), that’s why this type of piggy banks is known as the ‘green series’. It is not quite sure who produced them, because of the lack of a hallmark. Experts have reason to believe that Conta und Böhme from Pößneck (Thüringen) made them.
The piggybank marked JM is from Johann Maresch. The Siderolith- Majolica - Terracotta - Fabrik was established in Aussig an der Elbe in the former Austro-Hungarian Empire (now: Ústí nad Labem, Czech Republic). Objects made of siderolith and especially by Johann Maresch are rare and expensive.
Bunzlau, well known as earthenware brand, is a formal German city. Nowadays it is Polish and called Bolesławiec (Nieder-Sileziën). The Bunzlau earthenware is still produced there.