Table 2 Vaccine program of Layer PS(Parents) and CC(Commercial Chick) used in the experiment
| Age of chickenA | Layer PS | Age of chicken | Layer CC |
| Strain of IBVB | Live/killed | Strain of IBV | Live/killed |
| 4 days | Ma5C | Live | 4 days | M41 | Live |
| 1 week | QXD, KM91E, Ma5 | Killed | 2 weeks | K2 | Live |
| 5 weeks | Ma5 | Live | 3 weeks | K2 | Live |
| 10 weeks | Ma5 | Live | 5 weeks | K2 | Live |
| 13 weeks | QX, KM91 | Killed | 7 weeks | KM91, M41 | Killed |
| 16 weeks | Ma5 | Killed | 8 weeks | K2 | Live |
| 19 weeks | Ma5 | Live | 13 weeks | K2 | Live |
| | | 15 weeks | KM91, M41 | Killed |
| | | 18 weeks | K2 | Live |
A Age of chicken: The age of chicken when the samples were collected.
B IBV: Infectious bronchitis virus.
C Ma5: Infectious bronchitis vaccine serotype Massachusetts in worldwide.
D QX: Infectious bronchitis field serotype circulating in worldwide.
E KM91: Infectious bronchitis field serotype circulating in Korea.