Those are different for each species, the improvement of breeding groups was somewhat different. For example, with the rhinos, black rhinos, we have had a really famous Africa building plant by Heini Hediger. Building without right angles and without flat floors and so on. And we have had hippos, black and white rhinos in the house. But, as in many cases, animal spaces needed to become bigger and bigger. And so we, for example, gave away the white rhinos, where we have kept only a pair, growing up together and therefore never breeding. And so we have had so whole house for hippos and especially for the black rhinos. So we could extend the number of specimens of black rhino and this helped to succeed in better breeding successes.
