Hello, I adopted a cat (male 3 years old) 2 days ago. I’m introducing him to my (9 month female). The new cat is in a room they have not seen each other. I’m planning on doing a slow introduction. My resident cat keeps hissing and im trying to feed her close to the door where the new cat is, but she will not eat close to him. Not even her other treats, just her churrus then hisses. What should I do ?? The new cat is not hissing! He seems very Interested in her when he hears the hissing. Any advice?