is your run covered ? it will go bad fast if not.. The only place to do deep litter is a covered coop
??? My run is only partially covered, perhaps less than 10%. The rest is bird netting/ welded fencing over it, and it has "never gone bad" either fast or slow. The secret to DL is to have it nice and deep, (minimum of 6") and use a wide variety of materials. The poop simply melts into the ground. No odor. We just had several days of driving rain, and there was standing water in the run during the worst of it. Yes, the litter got wet, but it's so loose and spongey that it quickly absorbed all of the moisture. I can't imagine how nasty that run would have been if it was the bare ground fecal impacted soil that is often the paradigm of "what a chicken run should be like". Deep litter actually needs some moisture in order to compost properly. Just like a compost pile. If it's too dry, it simply won't compost. Of course if it's constantly too wet, it can go anaerobic.
A compost tumbler can be useful if one keeps a "manicured" yard, and does not have a lot of compostables. I have one, but really found that it was a waste of money, and it does not function as "claimed."