So, the price list differentiates the two:
Homing Pigeon: 100gm
Pigeon: 2cm
Basic Training: 1x cost.
Extensive Training: 2x cost.
Now what does "basic training" and "extensive training" apply to the two? For example, does the Homing Pigeon's "basic training" include carrying messages to locations? Can I train the normal pigeon instead to do it?