Yes they were at one time placed there. I understand your technical point, but semantics aside, they are no longer on a farm and have been living in the wild for a long time. I'm not referencing what they look like but how the birds at the pond live. They live in the wild.

A comparison to cats:

A feral cat is a domesticated cat that has returned to the wild, or the descendants of such an animal. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats have never been socialized. The offspring of a stray cat can be considered feral if born in the wild.