How long til they get along?

Tweet

We just got a new furbaby almost 2 weeks ago. She a beautiful calico adult female my 4 year old named Sybil. She has adjusted well as far as getting along with the kids, eating, drinking, using the litter box, and following household rules after getting told only once (so far!). The probelm we are having is that my original 2 cats Sabrina who is 8 and Luey who is 4 growl and hiss at her, then run so she runs after them in what looks like playing which then gets Sabrina or Luey hissing and spitting like they are being tortured! The funny thing is the first week she was here they kept trying to sniff at her while she was leeping and she'd wake up hissing. Is this normal behaviour? Will they eventually get along or am I going to have to look for another home for her?