Nest building

Is anyone else's bunnies building nests all the time?

Opal has been nest building for over a month now. I seem to find the beginnings of a nest each time i clean hers and the benjamins home. She also has a little bit of a bald patch developing under her tummy. Its not huge about the size of a 50p coin, but a bald patch all the same. Is this normal for a spayed bunny?

I think she may be using some of the benjamins fur too?

Just to add that they are pretty rubbish nests but a nest all the same.