Stocks were increased by animals transferred from other zoos that had been forced to close. Initially the zoo was given favourable food rationing quotas, but certain foods became unavailable and the price of others increased dramatically. Bananas were impossible to obtain and the supply of fish was problematic. As a result, the keepers were forced to experiment. The sealions became casualties of the food shortage when their keepers attempted to feed them strips of beef soaked in cod liver oil. Although they seemed to thrive on this diet, their digestive systems were unable to cope with the unusual food, and they eventually died of stomach ulcers. The lions' new diet was green-coloured horsemeat, and the monkeys were fed on boiled potatoes. The birds-of-paradise (lack of millet), and the penguins (lack of fish), were unable to adapt to their make-do diet and also succumbed. Vegetables were not in short supply however, as the garden staff grew lettuce, cabbage and carrots in the kitchen gardens.