why rabbit cry?

Question
Yesterday, I was having my Rabbit in my room I was working on the
computer and he was just laying on the floor, pooping at the same
time I suddenly heard a noise I thought from ouside but then after
less then  minue I realized its coming from him, it was a noise like
dogs do. I went to patt him and then  he stoped, I got worried I
take care of my rabbit very well, what is the reason he did that? I
have him now for more than almost two years and he never did
that. what that would be?

Answer
Dear Suzy,

If he was lying down and pooping, I have to wonder if he was asleep and having a bad dream.  Rabbits often sleep with their eyes open, and almost in a normal "waking" position, even when they are deeply asleep and dreaming.  Watch for eye and ear twitching, an odd "sliding" of the head into a lowered position, and general R.E.M. (rapid eye movement) associated with dream cycle.

I have known a couple of rabbits to vocalize in their sleep, and occasionally they would whimper and even do a very soft version of the "terror scream" that a very frightened rabbit will do.  

Was this a loud scream, a whimper, a soft moan?  Without hearing it or seeing the circumstances, I can't be sure.  But if bunny was sleeping, he might have been "sleep crying."

If he was awake, then I'm not sure what would have caused it.  If you can be more precise about what the vocalization sounded like, I might be able to help.

Hope this helps a bit, anyway.
Dana