Around 250,000 birds in Northern Ireland have been infected by a serious viral infection, the Department of Agriculture has confirmed.
Infectious Laryngotracheitis (ILT) has broken out on 16 farms, 14 commercial and two backyard flocks, the BBC has reported.
Veterinary officer Ignatius McKeown, who works at DAERA, told the broadcaster that ILT was a 'nasty viral disease from the herpes group'.
Symptoms observed in poultry usually include respiratory problems, increased deaths and loss of production.
Pathogenicity can vary with morbidity of 50-100 percent, and mortality usually 10-20 percent but sometimes up to 70 percent.
Poultry producers and backyard keepers across the UK have until recently been observing strict biosecurity measures on farms following bird flu outbreaks in winter.
Mr McKeown said on the new ILT outbreaks: "DAERA has joined with poultry producers in forming a group to formulate a plan to react against this disease and put procedures in place to control the spread.
"People with infected flocks are asked to keep poultry litter on their premises as long as possible.
"The longer the litter is kept on the premises the virus will reduce through time," he explained.
Transmission between farms may occur by airborne particles or fomites, DAERA has explained in advice posted on its website.
Good biosecurity and practices similar to those used for an avian influenza incursion are essential to keep flocks free from this serious viral infection.
Infectious Laryngotracheitis does not affect humans and has no human health implications.