is there a reason why the rabbit hutch is overrun by slugs is it the sawdust they like,the discarded food left over but they have dissapeared by morning
Yes, I think all those things you have mentioned would attract them, even the saw dust, so long as its damp.
They are more active during the hours of darkness or dull, over-cast, rainy days. they probably retreat to little nooks and crannies like under the hutch or under plants etc during the day. Hopefully other nocturnal prowlers like hedgehogs may help keep the numbers down a bit.
All the Best Tbird+