What is the shape of your rabbits poops? They could just be soft cecotropes. I’m not sure what it could be, sorry but feeding more hay should probably help. ❤️Btw if this has been going in for a while I would him to the vet.? Maybe you have changed his pellets or hay?

Don’t feed him alfalfa if he’s over 6 months old. It can lead to kidney issues due to the high levels of calcium. Alfalfa hay is only recommended as a bulk for underweight and sickly adult bunnies. A mini-rex should be getting only 2tbsp-1/4 cup of pellets a day. Large regular poops are fine. When you say soft do you mean like it smudges when you touch it? Or does it crumble?

Here’s a helpful guide on bunny poop http://www.medirabbit.com/EN/GI_diseases/drop/Drp_en.htm http://www.bunssb.org/bunnies/guide-bunny-poops/

It’s unlikely it’s the timothy, but you can try other brands and types to see what works. If it’s mushy and smears it sounds like it’s just a cecal left uneaten. They don’t always look like grapes/blackberries. What else is he on for a diet? What kinds of greens do you feed him and how much?

Do you give him any veggies?

Fluctuating poop quality can be reflective of a more fluctuating gut biome, so perhaps frequent bouts of gas, being given something that upsets his stomach frequently….

I would also examine his hay eating. Does he eat a lot, and how does he eat it? Do you notice lots of hay dropping, where he picks up pieces and spits them out? More hay typically leads to bigger poops, and consistent eating reflects in the poop. When Wick has a less-stalky/fibrous rotation of hay, his poop gets smaller; however, softer poops are different, making me think more towards some sort of gut imbalance.