So after pondering all the nasty possibilites that could be afflicting my little feral kitten, Rascal I think I have zeroed in on one or two, a bit closer to the truth.

When I went to take another look at her in the afternoon yesterday, she was rolling around on her back wanting me to pet her!  I felt her backside again but this time it felt more like dried blood or even tree sap!  Nothing was obvious on the fur on top, but a bit of fluffed of hair.  There would be no way she could move around like she was doing if she had broken any bones. *phew*

Today I rubbed a bit harder trying to ascertain the reason for the clotted hair when she
meowed and complained as if it were somewhat painful. So now I think she must have been bitten or injured on her back somehow.  I will keep an eye on her but I think I will still make an appointment for her at the vet next week to be neutered as well as have a good "going over".