She didn't look too bad to begin with : just a knot under her chin and one on her rump but as I started it was obvious it was going to be a bigger job that we expected. It helped that she was used to being handled and was very tolerant. All in all I shaved at least 12 knots off her. The one under her chin prevented her from raising her head properly and the on around her bottom kept her hip muscles permanently flexed. When I had finished, the first thing she did was to lie down in her run and stretch out- something that she was probably not able to do for quite some time.
I could smell dried urine as I trimmed around her tail and if I could smell it, then any blow flies around would be able to as well. She was very close to being a fly blown bunny.
She was lucky. The owners were sensible and called me to clip her off before any real damage was done ( apart from to her hairstyle- I'm no hairdresser!) but this summer many bunnies won't be as lucky.
If your rabbit is a house rabbit or is handled daily, the chances are you'll notice if it has knots but for those rabbits that live at the bottom of the garden and are lucky to get some food thrown at them each day, it may already be too late.
If you notice open sores on your rabbit or maybe even maggots, get your pet to the vet NOW. This is an emergency and waiting even an hour can reduce your rabbit's chance of survival.