Is round cage bad for birds? Round cage or rectangular cage?

Rectangular cages are definitely better. They provide more space for the bird to move around, fly or do other forms of exercise. There should also be some horizontal bars in the cage, so that the birds can climb around.

Birds do get scared of new things. My parrot is afraid of new people, loud noises, and the dog. The dog and bird are kept apart, although the dog has no real interest in the bird.

It's always good to get the largest cage that you can. Birds spend a lot of time in their cages, and need to move around.