Rabbit stress and loss of appetite?

by Savannah
(Spokane, WA)

Hi
I adopted a 1/2 year old Flemish mix male 4 days ago. He was re-homed because he doesn't like other rabbits in the home.

I told the previous owners I have a dog and they thought he'd handle it ok. He seemed to adjust to the move pretty well. His homebase is in the hallway (he is free roam) and there is a baby gate separating the living room where my senior dog hangs out and the bunny.

My bunny seemed eager to explore the living room, he was chewing and sort of pulling on the wires of the gate, so I let him out and he did amazing. He didn't seem bothered at all by my dog, who is very docile and well mannered.

He hopped right up to her bed and sniffed around her and on her. All seemed good. But the next day I noticed a significant decrease in rabbit pellets in his litter box. I looked everywhere for a place he might be going other than his litter box and there wasn't any.

He eagerly eats his pellets and greens but isn't eating enough hay. I kept him confined to the hallway and 2 bedrooms again the next day and things seemed to be moving along better for him, and again he was eager to come into the living room so I let him. And then this morning his litter box was completely clean of poop again.

After eating his greens and some hay things seem to be moving fine. So my question is, even though he seems ok with being around the dog, do you think it's stressing him out and that's why his appetite isn't very good or does it sound like there is another problem?