When to introduce previously sick chickens to your flock

[david4216]

Hi, three weeks ago I bought three hens and after a few days they showed signs of a respiratory infection (coughing, nasal fluid, etc.) I treated them with antibiotics and they were completely recovered by the end of the first week. They are still in quarantine two weeks after getting better and are vetry healthy, when should I introduce these in with my layers?? Thanks

 

[The Moonshiner]

IMHO never.
A lot of times birds can recover and look fine but are carriers forever and will spread the illness just the same as ones that are obviously sick.

 

[david4216]

But I thought when you use antibiotics it kills ALL bacteria in the body and I did keep redosing in case of resistance (I used penicillin and baytril and yes, I am now aware of antibiotic resistance associated with baytril)

 

[RodNTN]

@azygous @Eggcessive

 

[azygous]

Respiratory disease is a two-sided coin. On one side is a virus. The virus, being incapable of a life of its own must attach itself to an animal's cells in order to survive. In other words, a chicken virus moves into a chicken and takes up residence for the life of the chicken. In times of stress, the virus will weaken the immune system of the chicken, making it susceptible to bacteria.

That brings us to the other side of the coin. Bacteria are cells that move in to a chicken's body to take advantage of a lowered immune system. Respiratory bacteria hits a chicken when they're stressed. You can treat the chicken with an antibiotic which will kill the bacteria. But it won't affect the virus that has attached itself to the chicken's cells and is now part of the chicken.

By bringing in chickens that have just had a active attack of respiratory disease, you will be bringing in the virus that is part of their cells. Viruses shed and they become airborn and breathed in. The virus can also be passed from chicken to chicken in poop on the ground and sometimes through mating and some can even get into an embryo in an incubating egg.

When you import new chickens, even healthy ones, it stresses the chickens. This can lower immune responses and you risk having the new chickens get sick again as well as infecting every chicken in your original flock. Worst case scenario is that new chickens and the original flock can all end up getting sick. At the very least, the original flock will now carry a virus that they didn't have before you brought in the new chickens.