The first question in my new series “Answers from the Chicken Vet” came from Maryann B. in Maryland:
Q: “Referring to an article in this issue of Backyard Poultry written by a vet. The articles are well written and on pages 50 and 54. This vet also shows chickens. She talks about different diseases, one being Largngotracheistis which I believe is vaccinated with a live virus for this disease. Regardless, if using a live virus vaccine that would mean that chicken would carry the virus. If one chicken would be introduced to the vaccinated chicken the other chickens could possibly contact it. My confusion is most of the posts on Facebook talk about adding more chicks/adults to a current flock. I never read anything about vaccinating.
First, let me tell you some of the basics. Vaccines are viruses that have either been selected for being very weak, have been crippled in a lab somewhere, or have been outright killed (inactivated). The way they protect the bird from disease is by fooling the body into thinking it has been infected with a full-blown disease. (Think of your 10 year old son, back from his first schoolyard scuffle…”it was me or him, Mom”). The body then recognizes the disease virus, and keeps some immune cells in ready reserve to quickly mobilize if it sees the virus again.
- KNOW the vaccine status for your birds….what vaccines have they had….how long ago was it (protection wanes, the longer the time is since the last vaccination, the less reliable is the protection….the wall gradually crumbles)
- KNOW the vaccine/disease status of the incoming birds. This is always going to be questionable…unless you are buying day-old chicks, you can never be sure, but ask anyway.
- Try to match the two groups as best you can….if the replacements have been exposed to a disease your hens haven’t, find out if you can vaccinate yours ahead of the new birds’ arrival (usually 2-3 weeks before mixing is the ideal time to vaccinate)…remember to consider the new arrival too…make sure they are protected from the viruses your hens carry
- QUARANTINE the newcomers….ideally for at least a week or two. Birds shed virus much more under stress….if you can get them used to your yard, your water, your feed, your management, etc, etc before they are exposed to the stress of your already established hens, you will reduce virus shedding in the area of your hens by a huge proportion.
- Make the transition as stress-free as possible….short introductions, with a chance for the newbie to escape if necessary, etc.
Know the vaccine status of your flock and the replacements
- Match up the virus protection as best as you can
- Minimize stress at mixing
- Quarantine incoming birds to minimize virus shedding that accompanies stress
- Plan your replacements, so you can manage the immune status of your flock BEFORE the new birds are at the door
Hope it helps.
Dr. Mike Petrik, DVM, MSc
The Chicken Vet