Unfortunately, at an age under or at 1 year of age, the only reliable method of sexing is DNA Sequencing. As far as de-worming, you will need to have a veterinarian prescribe you a de-wormer and you will need to have the veterinarian weigh the birds. You don't want them to die from too much medication and there are also de-worming medications that are not to be used in birds. The veterinarians will have to write a prescription and we have found that many time, medications found in the U.S. are not found in other countries. This is why we strongly suggest you contact a veterinarian for the proper prescription.

The other issue is that worms or parasites may not be the problem with the low weight. The swans might be malnourished as they may not be getting adequate amounts of Vitamin A (cracked corn), minerals and vitamins (poultry layer pellets) and aquatic vegetation which can be supplemented using lettuce (completely washed with no insecticides/pesticides). Too much protein can damage their wings and cause a condition called angel wing, so you need to be careful about the protein content. Yes, they need protein, but too much can be detrimental. Poultry pellets will provide the necessary nutrients for the birds.

Your feeding them only twice a day may also be the problem. Swans need to feed at will so you need to place a feeder in the water so the birds can feed at will. Obviously, if they are not getting enough food, this will inhibit weight gain.

There is also the possibility that the swan may have some sort of an infection that is inhibiting weight gain. Both swans need to be seen by an experienced waterfowl or avian (bird) veterinarian to be weighed and examined. The veterinarian can also safely pluck a feather with blood and submit the feather to a reputable DNA lab for sexing.

Another less reliable method is to probe which can injure the birds if you do not know what you are doing. This is the least reliable method as the genitals are not fully developed under or at one year of age and therefore, what you think you have at this moment may not be actually what you have in a year. DNA Sequencing is the most reliable because it relies on genetic material. So, all of your questions and veterinary needs of the swans can be readily answered and cared for by a licensed veterinarian experienced in birds and/or waterfowl. The Regal Swan