Show cages are similar to the display cages you see in pet shops. They are usually plastic, with three solid sides and a barred cage front. This arrangement prevents the bird from having its feathers ruffled by all the hustle and bustle of the show going on around it, and also enables the judges to study the bird without background interference. At shows, it is always just one parakeet per cage.
Shows are all about the parakeets on show, but the cage has to look good too. Make sure that there is no rust or dirt in that cage. Also make sure to check with your local Budgerigar Society on how the cage should be set up. You need to make sure that the door-fasteners are secure. The cage will need a perch, food and water too - again, check with a seasoned parakeet exhibitor to fine-tune your cage.

When exhibiting birds, it's one parakeet per cage
Parakeet Cage Fronts
You will often see advertisements for cage fronts on sites selling parakeet paraphernalia. They are simply the front section of a show cage, and come in various sizes, usually with a single door for inserting and removing food and water. Many people who exhibit their parakeets at a bird show take to DIY mto craft the ideal “show cage”. As these are specialist containers, pre-made models are hard to find.
Anonymous, 12 April 2021
I have two budgies one male and one female they have been together for about a month but they still aren't breeding the female is actually larger than the male but I did some research and it says they can still breed I don't know I just need some help on what to do because I really wanted them to have babies please help!!