Each bird was vaccinated by commercial Newcastle Disease Virus (NDV) vaccine via eye-drop at day 6 of age, and via
drinking water at days 16 and 26 of ages. Additionally, at 21, 33 and 42 days of age two birds from each pen were bled
from the brachial (ulnar) vein and the sera content was collected. The serum samples from each treatment were tested for
antibody to NDV by enzyme-linked immunosorbent assay (ELISA) using ‘Newcastle Disease Antibody Test Kit’ from IDEXX
Laboratories Inc. (Westbrook, ME, USA).