Allpress says she has seen more than a dozen roosters appear at the lake in recent months and five new ones have appeared during the past week.
"Some have been run over, others have disappeared and of course they are always fighting.
"That can cause life-threatening injuries and it is awful to think they die slowly and painfully - it's cruel."
Abandoned birds have also been seen at rest stops, reserves and Virginia Lake is a popular dumping spot.
Ron Pratt of Manawatu Poultry and Pigeon Club has been around poultry for 60 years and says he understands why people don't like killing young roosters.
"I still don't like doing it myself but it is much kinder than dumping them to fend for themselves.
"They might be alright for a while but they are likely to be killed by dogs or run over."
Pratt says roosters inflict bad injuries on each other when they fight and infections are common.
"If people are keeping chooks in their backyards to lay eggs, they shouldn't be keeping roosters."
An alternative to dumping roosters and unwanted hens is to sell them to people who will kill them humanely.
One man who does not wish to be named says he often buys unwanted birds and as a former freezing worker, he knows how to dispatch them quickly.
"If I am keeping them for a few days, I feed and care for them well - they don't suffer.
"I have approval from animal welfare."
He says anyone who has unwanted birds should contact the Wanganui Poultry Club and they will contact him or another approved buyer.
