I’m working with a horse currently who has some slightly odd symptoms
- very stiff back end to the point where I can rarely pick up her back feet, especially her left
She doesn’t act crappy or painful though - which is where I get confused.
Yes, horse is sound.
It possible that she needs more muscling and conditioning/fitness, but most horses (especially a young one) should not have any problem simply picking up a back foot. If she can't do that simple task, that is a big red flag for me.
Horses don't have to be all-out limping in order to have a pain problem somewhere. Most often, there is a change in their performance or behavior instead that alerts the owner there is something amiss.
Dull coat can possibly be back of proper nutrition or possibly ulcers (and yes, even laid back horses like this one can get ulcers).
Horse has had a physical exam and blood work done - everything was good.
To me, this means the vet literally "looked" at him, checked vitals, and said "he's good".
As others have already suggested, encourage the owner to take the horse to a lameness vet who can do flexion testing on the horse and evaluate his movements.
The overall "laziness" is not a problem (because it just sounds like the horse is lazy) but not being able to pick up a foot is.