Moist poop?!?!

Hello. I've had my chin since May and in the last day and a half I have noticed that his poop is more wet. It's not runny or diarrhea, but it's not the hard solid pellets that it usually is. I haven't changed his diet at all and he doesn't get treats. I feed him the fiesta mix pellets every day (2 tbs) and timothy hay once a day (at night). Is this something I should worry about or is there something I can give him/ change that would bring the poop back to normal?

Thanks!!