There could be any number of reasons for the death. Aspergillosis is a fungal infection that is usually a major concern for young birds. Moldy wet straw or hay can be one of the causes for the fungal infection. However, there are many other causes such as egg sac peritonitis (in which the egg sac does not get expelled from the abdomen and peritonitis sets in). If peritonitis is the cause, no fungal or other parasitic medication will be of any use. Even an antibiotic can be useless in this instance. Therefore, to really understand what might have been the cause of the death, you would need a necropsy performed and even then, at that young of an age, you may not get a positive result of the causative agent. We’re not sure that these type of medications can be used, so you might check with Bob Knox at (info@canadiangoosecontrol.com) or a local veterinarian dealing with waterfowl. Both of these resources will be helpful to determine the exact medications you might be able to prescribe as well as correct dosages. The Regal Swan