Hi, welcome to the forum, glad you joined!
You are dealing with living animals so there are no firm fixed numbers that work for everyone. Each animal has its own personality, some like close company, some don't.
Are they baby chicks or are they older? If they are babies, by the time your weather warms up they can go outside. Young chicks do not need that much room. Is this a brooder in your heated house and the cage will be totally separate?
For most people 18 square feet total can work for three hens. If it is just a brooder until they get bigger and can then go outside it is huge.
I don't like it being that thin. One chicken can't walk past another without getting pretty close. Most will be OK with that but some have the personality that they don't like it.
There are too many unknowns for me to be able to tell you that it definitely will or will not work. I'd probably try it.
