I should add... even with my EE only getting 5 hours of sun a day, she STILL manages to lay an egg every day, but the shell quality is able to stay healthy enough. It's crazy.
Thank you for the ideas!
The lethargy is only right before she lays a weird egg/eggs or if she's acting like she needs to lay (nesting down in a box making noises like she's trying to lay). After laying she always perks right up back to normal again. No perceptible respiratory symptoms in her...
Sadly, my 2.5 y/o RIR (hybrid variety) seems to be dealing with reproductive issues. Over the last couple months, I've noticed her slowing down here and there, and also her eggs becoming a bit more fragile and wonky looking--i.e. excess calcium deposits, loss of pigment, weirdly elongated...