WARNING: The following update includes some discussion of rabbit waste products--we're talking serious bunny poop talk, people. We recommend not reading it on a sensitive stomach or while eating.
After posting about Mickey's digestive woes last night and getting the patient back into his cage, I checked the litterbox and found a three-inch-long string of shiny gelatinous brown beads all strung together with hair; a poop chain. If it had been any longer, I might have had a poop bracelet.
As for the patient, he promptly attacked any and all food waiting for him in his cage and began to chow down. This morning, he was busy flinging his greens dish around and trashing his cage, so I would say that he's feeling better. His cage litterbox wasn't showing a lot of poop, though, so I'll be checking it again later after he's been fed again.
Called the vet, but decided an actual visit wasn't necessary for now. She agreed with my diagnosis of hair blockage, and said to keep doing what I'm doing and bring him in if anything changes.
Plan of action for the weekend is to keep putting stuff in him and make sure stuff is coming out. There will also be extra grooming involved to get as much loose fur off of him as possible so it's not getting inside him.