i have purchased 2 5 month old black swans 3 weeks ago-there were 3 but one died of respiratory illness at 2weeks after purchase. the other 2 are not eating despite trying different food-lettuce, fruit, swan feed. they have not eaten in 3 days...what should i do? are the mourning the death of the other swan? are they ill? sexes of all swans are unknown at this time. i have never owned swans before but raise 15 other types of fowl with great success. thank you for your time and consideration and you expertiese is much apprectiated. barbara