We purchased a sibling pair of mute swans about a month ago and was wondering how we could go about sexing them. We think they are male and female since one is noticeably larger than the other. I seen someone on here who had a female juvenile for sale and I would like to replace our probable female with this one so our pair would be unrelated. So how can we find out their sexes, how long before they pair up and do they mate for life and would I be able to get this third one and keep it until we find our which one is the male? Thanks in advance for the responses.