They were signed as 'Blick Hinter die Kulissen" which it seems I should have translated as "behind the scenes" rather than "off-show" (my mistake comes from the fact that 'Hinter die Kulissen' on zootierliste is used to denote something being off-show.)
So yes, you can walk down the path, though it comes to a dead end. The purpose of this bit is to highlight the behind the scenes breeding work that Weltvogelpark Walsrode does to the average visitor who may not realise the park is anything more than a display of pretty birds. There is a sign leading to it and the bit in English at the bottom says:
"Weltvogelpark Walsrode - more than a bird park. Our important work in the park: bringing the beauty and diversity of birds closer to you, giving you a day full of wonderful experiences. Our very important work: 'behind the scenes' breeding programs for conservation of endangered bird species. In order to bring you even closer to this work, we invite you to have a look at some of our conservation and breeding aviaries.
It is in these aviaries that we specifically breed endangered bird species to serve their international conservation and protection programs.
Help to support these programs by donating to the Weltvogelpark Foundation or become a sponsor of our birds, cages or enclosures. Further information on: www.weltvogelpark.de"