I have two, and one of mine is just the same!! She was abused as a baby and we rescued her just in time really (when she was only 6 weeks and was being used as a ball in 'catch' for the neighbourhood kids).
Because she was so skinny and tiny when we got her we fed her basically anything she would eat whenever she wanted to eat.... so now she takes it as her due and went in our neighbours house the other day to steal a packet of their chicken nuggets off the table :lol:
Norti tortie!!!