We've tried all times of day, after feedings, after nap, etc. She does the best in the morning, but still not for long. She always smiles and plays with him if I'm holding her, but if he takes her she screams.
I have left the house a couple of times for an hour or so, and she does okay for a little while, then starts in again. Whether I'm there or not, she will usually scream herself to sleep (even if she just woke up from a nap) within ten minutes, and then when she sleeps she heaves these big sobbing sighs.
If she doesn't scream herself to sleep, her cries just get more and more hysteric until I come get her.
Last night I was gone for five minutes nursing my older DD, and when I came back she was beet red, sweaty, and sobbing uncontrollably.
She also screams if I leave the room and only Daddy is there. She will look around, see the room is empty of mama, and then scream. She will even see a closed door and freak out.