Bald Bunny Bum

Question
Hiya...

Archimedes, my crossbreed-but-mostly-lionhead bunny has
started to shed his spring coat, and he's so fluffy I usually sit
him in my lap and give him a gentle plucking when he moults.
He loves it, too.

This time though, he'd moulted all the way to his skin around
his lower back, just above his tail. His moulty bits brushed out
gently just like every other time so far, but where he'd normally
have a new coat of short fur underneath, he's utterly bald.

His skin's soft and unbroken, and he clearly doesn't care and
probably hasn't noticed, since that's the bit of his bum he can't
groom himself, and he lives with cats who don't know how to
groom him. There's even a bit of very firmly-anchored new coat
in the middle of the bald patch.

I definitely didn't do any overplucking, and he was totally
relaxed during it, and even now is sunbathing, even though I
keep trying to shoo him into the shade in case he gets sunburn.

The only thing I can guess it might be due to is the fact that he
hasn't got to go out for a couple of weeks, as I've been working
at the other end of the country, and my mum couldn't catch him
if her life depended on it. He normally has the run of the
basement, which does have good light for half the day.

Maybe he's had a lack of light, or maybe he's sat with his bum
up against a can of paint thinner or some other such silliness,
but his skin's fine and he's not irritated.

Granted, it's really hot these last few weeks. Maybe his new coat
just didn't synchronise with his moult?

Answer
Dear Tom,

Sometimes a bunny will have a real "coat blow" and leave bald spots where there should be new fur.  As long as the underlying skin looks healthy, it's not a cause for major concern (except for the sunburn potential you rightly noted).  If the fur doesn't start to grow in the next week or so, there could be other reasons for the excessive fur loss.  This article might help:

www.bio.miami.edu/hare/furloss.html

Hope that helps!

Dana