Our new bunny Horatio does this too sometimes while he is eating! He did it a lot the first night we got him because he was so exhausted from his long journey - It was a little scary to watch at first! I can see him do it a little now (he just blinks slowly and his head will tilt up and down just like when a human is trying not to fall asleep in a lecture for example
), but he will still do a big flop when I come to put him and fall asleep while I stroke him.
I wouldn't be worried at all. It's nice he is comfortable enough to fall asleep anywhere/anyway he likes and not be worried you will eat him! And it means you have tired him out enough so he doesn't make lots of mess in his cage when you are out. At least that's how I see it
Edit: Also, how old is he? Ray is only 10 weeks but I was still surprised as how much he sleeps. He loves to just go and flop down and be rubbed while he sleeps for hours on end! He will be active and run around, but then he is very content to sleep the rest of the day
Some bunnies are more active than others though - Our Poe would sleep a lot during the day but he was still bounding around exploring and making sure he was putting me in my place in between those naps, whereas Ray will run around and do lots of binkies but he still has a quite nature in general. Everyone is different
I myself prefer the sleepy bunny
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