I noticed while I was there that the bald eagles were tied to their perch while in their pen. Isn't this inhumane to make them stay in one spot all day?

There is a bald eagle there but it had lost part of its left wing, and would not be able to fend for itself in the wild

They're not out there all day. And the tether give them enough slack so they can hop down and walk around on the ground if they so choose

Signs near the bird of prey exhibit explain the concept of tethering employed by the Farm, which is a practice perfected over the past several thousand years that allows the natural behavior of these birds to perch for a large portion of their day.