My parakeet is puffed up on the cage floor. Is she sick or egg-bound?

I am sorry to hear about your concern for Julia. She is a pretty parakeet! If she is sitting on the floor of her cage for long periods puffed up this is concerning. Any time a bird is having its feathers puffed up for long periods of time this can be a sign of illness. While birds who are laying eggs will go down to the floor of the cage if they don't have a nest box area they wouldn't normally stay on the floor of the cage for long periods each day. I would be concerned your bird could be egg-bound, meaning she could have an egg that she is having trouble laying. You may be able to tell this if you bird is handleable and you can flip her over to look at her vent/cloaca area. You may see a swelling here or palpate a large firmness in the area if she is egg bound. If you feel this, I would recommend getting her to a vet right away, or if she is continuing to spend long periods of time on the floor and puffed up, she should see the vet to check for other signs of illness.