Certainly, one or both could be infertile. The only way to find out is to check hormone levels and an anatomical exam. However, trying to determine the cause or treat could be costly and still not render any results. There are also two other possibilities: both birds are the same gender, probably males because they will still build nests but not produce eggs or the swans are older than stated. Why does the owner want to sell the birds? We are not suggesting an unscrupulous owner/breeder, but we have certainly heard some horror stories. One of the major concerns is getting birds of the wrong gender which might have occurred when the owner got the birds or thought he had a certain gender without testing. If probing was conducted and the birds were very young, then this is the least reliable method of determining gender. DNA Sequencing is the most reliable and can verify the gender at any age with a feather sample submitted by an experienced veterinarian.

However, there is a more important issue. No matter the gender of the swans, they have bonded. It would be extremely inhumane to separate them and no guarantees that they will ever re-pair with another swan. Our suggestion would be to take the swans knowing they may never produce, but this is not a bad thing. You will not have the added burden of extra veterinary care such as pinioning each year or having to find homes for the cygnets every year once the parents start chasing them from the habitat due to a new breeding season. Also, by law you may need to have a breeder's license/permit for a breeding pair. So, you should check your local laws. We hope this information is of benefit. The Regal Swan