Massive weight-bearing hinge plates carried huge doors. The plates were as large as 18" in depth and 12" in width, embedded within the brick layers. Some stable walls were three bricks thick.
The original 100 year old wood frame peeks out from under the plaster. The marginally protective bars have trapped a screen that has probably not been used for the last 50 years. This "window" has been created in part of the space that was originally occupied by a stable door. The infill space is likely composed of an odd collection of various bricks or blocks - now hidden from view.
Clearly the flimsy nut and bolt in the right hinge plate served a less demanding function than the original pivot point hardware.