Vaccinations in broilers should be strategically timed to provide immunity while minimizing stress and ensuring optimal growth. Typically, day-old chicks receive Marek’s disease and Newcastle disease vaccines at the hatchery. At 7-10 days, a booster for Newcastle disease and infectious bronchitis is often given. At 14-21 days, infectious bursal disease (Gumboro) and sometimes an additional Newcastle vaccine are administered. Depending on local disease risks, at 28 days, a booster for Newcastle or other regional diseases (e.g., fowl pox or IB) may be needed. Vaccines should be scheduled during cooler parts of the day, with minimal handling stress, and integrated with biosecurity measures to ensure maximum effectiveness.