I wonder if anyone could give me some advice?

I own a Staffordshire Bull Terrier and she was rehoused with me when she was 2 years old. I was told a brief outline of her history that she was beaten and mistreated.

I have recently noticed that she snaps at the other bitch (around 1 year old) and gets very jealous.

I

Bitches can get a bit "grouchy" around each other during their season . Does it seem to be all the time that she is like this or does it coincide with either of their seasons ?
Lesley