Hoof care and falling down/locking stifle
I just discovered that my 19 yo TB is falling down at night (someone who lives in the barn apartment at my boarding facility saw him fall down), apparently when he is trying to sleep. She also saw him with a locked stifle one time, though I have never seen him have this problem at any other time. My trainer said this sometimes happens to older horses, and he may not be laying down to sleep and so may be sleep deprived. I can't really tell if he is laying down in his stall. Separately, I have noticed that he trips a lot, both when lunging and under saddle.
The person who saw him fall down (apparently, this happens a lot but she didn't know what the sound was until she actually saw him do it one night) told me that it could be due to problems locking his stifle (and unlocking, I guess, since she saw him with a locked stifle), and that there are shoeing/trimming techniques to help this issue. So, I'm not sure if his falling down is due to sleep deprivation or due to a stifle issue. Also, I'm wondering if his tripping is related. He is due for his next farrier visit in about 2 weeks, and it would be helpful to know if there is something I should ask the farrier to do differently. He currently wears shoes on all four feet. I don't have pics of his feet but will take some (he is wearing snow poppers, so I can't get good pictures of his frog, etc., though).