03/15/2010 (6:48 am)
Owners need to take steps to protect chicken flocks
Deborah Rich, Special to The Chronicle
Saturday, September 30, 2006
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/09/30/HOGDRLEJ9M1.DTL&hw=poultry&sn=001&sc=1000Backyard
Chicken coops don't have to be a breeding ground for avian influenza virus.
It's all about biosecurity. That's the word poultry advisers, cooperative extension agents and the like are using with people who own small flocks of poultry.
"The emergence of the highly pathogenic H5N1 avian influenza virus means that we have to develop new strategies to keep these birds safe," says Carol Cardona, a UC Davis poultry veterinarian.
Nobody knows when, or even if, the highly pathogenic H5N1 virus, what Cardona likes to call the "bad bird flu," will arrive in the United States. Nor do we know how much trouble it will cause. But the virus has demonstrated a tendency to travel and has a nasty reputation.
Highly pathogenic H5N1 was first detected on a domestic goose in Guangdong province in China in 1996. The next year, it was found on poultry farms and in live bird markets in Hong Kong. Since then, the virus has infected domestic flocks in South Korea, Vietnam, Japan, Thailand, Cambodia, Indonesia, Laos, Malaysia, Russia, Kazakhstan, Turkey, Romania, Ukraine, Iraq and Nigeria.
All avian influenza viruses originate in wild birds, especially migratory waterfowl and shorebirds.
Scientists believe that highly pathogenic H5N1 began life as a low-pathogenic influenza that mutated and increased in virulence once transmitted to domestic flocks. Not only does the virus devastate domestic flocks -- 80 to 100 percent of infected chickens and turkeys die within 48 hours -- highly pathogenic H5N1 raises the specter of a lethal new human influenza virus emerging.
The World Health Organization reports 246 confirmed cases of humans infected with highly pathogenic H5N1. Of those infected, 144, or 59 percent, have died.
Still, these deaths have almost all been caused by bird-to-human transmission, and the virus has yet to mutate into a human influenza.
"Gross infection" from handling visibly sick and dying birds is necessary to pass the virus from birds to people. "People don't have to go out and kill their chickens. They don't need to feel like they are putting their families at risk," says Cardona.
If the bad bird flu does infect domestic flocks, just how much havoc it will wreak will depend upon how quickly we can recognize infected birds and limit its spread. That's where biosecurity comes in.
Eva Wallner-Pendleton, avian diagnostic veterinarian at Pennsylvania State University, finds reassurance in the fact that H5N1 was detected in wild birds in several European countries in 2005, but the virus spread to domestic poultry in only a few instances, most notably in Romania.
Given the surveillance and biosecurity measures in the United States, Wallner-Pendleton believes that wide-scale spread to commercial poultry is unlikely here. "As a veterinarian who has seen how we have contained mild cases of bird flu here in the United States, I am far less concerned than some of the folks in public health," she said.
Biosecurity is a set of basic concepts geared toward preventing the introduction and spread of disease. Many are nothing new to industrial poultry farms that have to work hard to keep diseases at bay.
However, the USDA and land grant college extension agents are now urging small-flock owners to think along the same lines.
"With the highly pathogenic H5N1, you can have two flocks side by side: one is outdoors, in sunshine, with optimal space requirements, and the best possible feed; the other flock is indoors, crowded, without enough sunshine or fresh air, and poor feed. If you take this highly pathogenic virus and infect it in both flocks, they will both die," says Wallner-Pendleton.
The most important thing to remember is that domestic poultry do not originate the virus. Influenza viruses must be carried into the flock. Wild birds, especially migrating waterfowl and shorebirds, have the potential to be vectors, but so do visitors who have been bird hunting, or who picked up an infected dead bird, or who come to your flock after visiting another flock.
This latter category can include neighbors, health inspectors, feed store drivers, the UPS delivery person and the veterinarian. It also includes yourself.
Keeping wild birds away from your flock is the easy part. Placing food and water under cover will help prevent your backyard or ranch from becoming a favored resting place for wild birds. Outdoor pens, cages and runs can be covered in fine netting.
It takes more effort to keep unwashed hands, shoes and wheels away from your flock. Cardona suggests that small-flock owners wear clothing and shoes that are clean or have been used only around their own flocks and that they keep visitors to their flock to a minimum.
Owners can isolate new birds and returning show birds away from their flock for three weeks.
"Traffic flow should always be from your flock to the new or returning birds and never in reverse without a change of clothing and a shower," says Cardona.
Basic sanitation goes a long way toward preventing the spread of disease. "Influenza virus is not a super-bug by any means," says Wallner-Pendleton. "It does not survive a long time in the environment, especially in warm, dry conditions. The virus survives the longest in a cool, moist environment. Most disinfectants readily destroy the virus."
Extension advisers urge poultry owners to wash hands with soap and water after handling birds, their feces, coops, waterers or feed trays. Shower and change clothes between "dirty" jobs like manure pickup and dead bird removal and "clean" jobs like working with live birds, gathering eggs and feeding.
Keep manure away from areas where lots of people walk, and do not leave small children alone with birds or manure.
Compost feces, adding sufficient sources of carbon to generate heat in the compost pile.
Finally, simply checking your flock every day for signs of illness or suspicious deaths can help check the spread of disease. To remove a suspect dead bird, cover your hands with a plastic bag, invert the bag over the bird and wash your hands afterward.
California law requires anyone who knows or suspects birds are infected with avian influenza to report it to the California Department of Food and Agriculture or the USDA.
The USDA operates a toll-free hot line (866) 536-7593, staffed by veterinarians to assist you when you have sick or dying birds.
Just who has a chicken coop?
Data is very scarce on who in California raises backyard chickens. They do not have to be registered, so it is difficult and costly to get a handle on the number of backyard flocks.
Steve Lyle, director of legislative and public affairs at the state Department of Food and Agriculture, said in 2003 that the CDFA surveyed approximately 300,000 homes in parts of Los Angeles, San Bernardino, Riverside, San Diego, Kern and Ventura counties and found that 75,910 had backyard poultry.
No such statistics exist for Northern California.
-- Deborah Rich
Deborah K. Rich
Saturday, September 30, 2006
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/09/30/HOGDRLEJBG1.DTL&hw=poultry&sn=003&sc=569
Joel Salatin raises 12,000 broiler chickens a year without donning designated coop shoes before tending his birds. He doesn't limit visitors to his farm either.
"What we count on is raising chickens with real healthy immune systems," says Salatin. To do so, he raises them outdoors.
"You can't lock these birds in a 15,000-chicken house, and dope them up, and expect them to have an immune system. They're going to be susceptible to every little thing that comes along."
But Salatin doesn't expect the U.S. Department of Agriculture to side with him if a highly pathogenic form of avian influenza arrives in the United States.
"They'd shut us down in 24 hours," he says. He recalls how the industry was quick to blame waterfowl, backyard flocks, and free-range poultry for transmission of a low pathogenic avian influenza during an outbreak in his home state of Virginia four years ago.
"I was called a bioterrorist," he said.
State and federal agents tested more than 90 backyard flocks and 300 Canada geese from 23 sites near infected commercial poultry, but despite initial suspicions that wild birds or outdoor poultry were the disease vectors, no signs of infection were found.
The 2002 outbreak resulted in the land filling of 4.7 million commercial turkeys and chickens.
Outdoor chickens are critical to Salatin's Polyface Farm in Swoop, Va. Considering himself first and foremost a grass farmer, Salatin maintains the health and productivity of his farm with a grass, cattle and chicken "crop rotation."
In his book, "The Omnivore's Dilemma," author Michael Pollan profiled Salatin's operation, presenting it as a counterpoint to industrial organic operations.
Outdoor chickens, however, become immediately suspect when avian influenza appears in neighboring flocks.
Wild birds carry avian influenza viruses, and flocks housed outdoors are more likely to come into contact with the feces of infected wild birds.
But Salatin doesn't believe that housing thousands of birds together inside is the answer. "The key is to learn how to manage outdoor systems hygienically," he said.
According to Salatin, a hygienic system does three things.
First, it reduces the pathogens' access to hosts by limiting the time birds spend in their own droppings. Secondly, it spread birds out to reduce the opportunity for a virus to build up and to gain in virulence. (The fewer birds available to the virus, the less virulent the virus can become lest it kill off all its hosts.) Finally, in a hygienic farm system, feather, feces and offal do not travel and spread the disease.
Salatin "pastures" his broilers in 10-by-12-foot floorless mobile cages, each cage housing 70 birds. Every morning, Salatin eases his mobile chicken homes onto a fresh unsoiled patch of grass.
The chickens spend the day eating grasses, worms, and insects, depositing their nitrogen-rich droppings in the field. Chickens will not be "pastured" on the same piece of ground again until months later.
Once a week, Salatin slaughters several hundred of his chickens at the farm. He sells the plucked and cleaned birds directly to customers at the farm's store and at farmers' markets, as well as through local shops and restaurants. All chicken feathers and offal are composted on the farm.
Salatin offers backyard flock owners the following four tips for keeping chickens healthy:
1) Use portable structures if at all possible. Salatin says portable coops, which keep chickens on fresh ground, out of their own manure, are even more important than having fewer birds per coop. Alternatively, have two to three pens and move chickens into a different pen every few months. Leave pens time to air out and be "disinfected" by soil microbes between periods of occupancy.
2) Don't let laying hens get old. Ideally hens shouldn't be kept longer than three years, with four years the absolute maximum for keeping hens. "You want young, strong hens whose immune systems haven't been compromised by aging."
3) Make sure that the feed is not genetically engineered. "There's just too much about genetically engineered grains that we don't understand."
4) Finally, enjoy them. "And don't believe everything you read in a USDA bulletin."
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