Thanks for the input
I was trying to figure out what was 'normal' before approaching my BO about my horse's stall.
A few times in the past couple weeks when I've gone to see him there's been a very noticeable ammonia smell. His stall is very well ventilated, so I know that's not the issue. I suspect there's either a different person mucking out the stalls in my end of the barn now or the BO has asked them to use use less shavings. Either way, his stall needs to be cleaner than it is!