to give update on my situation. After 5 weeks my new female finally ate, however, she did not attack the rat. She merely smelled it, so I left it in her cage and after about 20 mins she started eating it right away. I did not mind cause I was happy she ate. However, this week, she refused again. I do not know what I am doing wrong.

Just to let you guys know, if any of you had similar situation and solved it.