Yes, swans can get lice. It was shown in the seventies, (you can google the research) researchers found that the lice could cause heartworms in the swans. We were recently in England and saw large white lice in the swans. They were so infected that once you touched the swans, the lice were crawling up our hands and arms and even on our jackets as we held the swans.

I would suggest that you contact Wendy Hermon (Swan Lifeline Rescue facility, Eton, England) to determine what measures they use to eradicate the parasites. Pesticides or other insecticides that may commonly be used over here, may not be the best for the swans and may even cause them to become seriously ill or even die. Wendy and her staff encounter these and other parasites on a daily basis and can provide you with an enormous amount of information regarding eradication and even possible prevention in captive flocks. The Regal Swan