More expensive initially, but they can be trained to return to your loft, allowing you to use the same birds repeatedly for flushing drills.
Some farm supply outlets can order live birds or connect you with local suppliers. buy pigeons for dog training
Often cheaper (averaging $5–$20 per bird), but they are usually considered "one-use" birds as they will not return to your coop once released. More expensive initially, but they can be trained
Search for "homing pigeons" or "feral pigeons" on Craigslist or dedicated hunting forums. More expensive initially
These are young birds that have not yet learned to fly well. They are ideal for building a new homing flock because they can be acclimated to your specific location. Training Best Practices “Puppy Training” Pigeons Rescued - - Palomacy