HONOLULU -- The Kauai Humane Society has begun seeing a number of sick and dead chickens on the Garden Isle.

A few of the dead birds were sent to the State Department of Agriculture's laboratory on Oahu.

The Humane Society is concerned that someone might be poisoning the chickens to curb a nuisance problem. So far, they have collected 15 dead chickens and three sick ones.

Dr. Becky Rhoades said the initial necropsy showed no signs of poison.

"It did have nasal discharge and red eyes like with a bacterial infection. My guess is we have a bunch of sick chickens," Rhoades said.

Rhoades said that too many people are feeding chickens, causing overpopulation.

Bacterial infections are generally not contagious to humans or other birds. It is unlikely the chickens died of avian influenza or West Nile virus, officials said.