Periods When Chickens Should Not Be Vaccinated

　　1. Do not vaccinate during the incubation period or when the flock is not fully healthyWhen a flock has just recovered from illness and the body's various functions have not yet fully returned to normal, it is recommended to use antiviral Chinese herbal medicine for 3 to 5 days before vaccination, stop for 1 day, and then carry out vaccination, which gives better results.

　　2. Moving the flock and vaccination should not be carried out at the same timeInjecting vaccines when chickens are being moved means stacking multiple major stressors together to act on the body at the same time, which results not only in no weight gain after the move but actually weight loss, and in severe cases a considerable number of chickens will stop eating, develop diarrhea, or even die from the stress. It is recommended to wait 3 to 5 days after moving the flock before carrying out immunization.

　　3. Newcastle disease strain I vaccine should not be mixed and injected with other vaccines such as fowl pox vaccineBecause Newcastle disease strain I vaccine can strongly induce the body to produce anti-interferon, which greatly reduces the immune effect of other vaccines given at the same time, resulting in immunization failure. It is recommended to give Newcastle disease strain I vaccine and fowl pox vaccine etc. at an interval of 1 week.

　　4. Do not vaccinate during the period when the egg production rate of chickens is risingThis is because after laying hens begin laying, due to the huge physiological reaction, the body's defense functions become very fragile and they are very susceptible to disease. Therefore, it is not advisable to vaccinate laying hens during this period.