She was rushed to the Companion Care Cathedral Veterinary Surgery in Ely, Cambs., by a resident who witnessed the savage attack.
Miraculously, Dylis did not sustain any fractures or wounds,and following daily hydrotherapy sessions she was able to be released back onto her lake just 10 days later.
Sally Ann Halliday, practice manager at Cathedral Surgery, said: “Dylis had been badly beaten and was unable to stand or move. One of her wings was hanging by her side.
“She was very carefully examined; no fractures or wounds were found and her injuries were determined to be those affecting the central nervous system. She was treated accordingly.
“Over the next few days she became more aware and started to respond normally – eating and drinking although still unable to stand on one of her legs or lift her wing.
“One of our nurses took her home to larger quarters and gave her daily hydrotherapy sessions.
“She responded wonderfully well and it became apparent she was improving in leaps and bounds.
“One morning Dylis made it clear she felt strong enough to go back to her home – flapping her wings strongly and using both legs as she waddled around the garden.
“Ten days after she was taken into our care she was released back into the wild – quacking loudly with delight when she discovered her friend on the riverbank.
“A really happy result thanks to the love and care she received from both her rescuer and the team at our surgery.”
The incident has not reported to the police or RSPCA.
A spokesman for pet insurance company Animal Friends said: “It seems as though we hear new stories every week about unspeakable acts of animal cruelty.
“As a renowned nation of animal lovers it’s always so jarring to hear about cases like this. Dylis was very fortunate to have received such loving care, and we wish her the very best in her recovery.”