Dispenser/Animal Interactions

Dispensers can shoot eggs to make automatic chicken farms in a tiny space, and can shear sheep to make automatic wool farms in a tinier space.

Why can't dispensers milk cows with empty buckets or breed animals with crops? They should be able to. No in-game logic would suggest otherwise (especially if shears in a dispenser work on sheep and mooshrooms).

Hostile mobs can be farmed passively with enough space and a little bit of redstone. Passive mob farms should receive the same level of automation potential with the small addition of these two dispenser-to-animal interactions.