A typical example of the small, hobbyist-run bird parks that are ubiquitous in this part of Germany. They are so many and so close that it is easy to do 7 or 8 different collections in a single day. We asked around at the Zoohistorica event last year and at least one person had done 11 in a single day.
They're variable in quality - this one is above average for its type. Heppenheim and Viernheim were the other two stand-outs of the ones we did.