No, we're not administering them the same way but I found the answer I'm looking for in a paper though. Thank you for your consideration! Let me know if you have further questions for your own research.
Apsolutelly the best mode of vaccination is respiratory route. The particle should be 2-5 microns in diameter and specific refracterity to ND (not antibody development) is developed in 24 hours (vaccination of newly hatched chickens) due to interfereance of vaccinal virus in the cell to the virus of the same genome (eg pathogenic NDV). Parentheral injection is time consuming and the immunity is developed not erlier than 7-8 days (inactivated vaccines).
There are so many factors influencing the different ways of administration of vaccines that a simple answer to this question does not exist. Dose, immune status of chickens, accompanying microorganizms, toxins, type of vaccine, age of birds, etc, etc, etc.