I wouldn’t normally have a go at someone like this, but it seems you haven’t listened to most of this critical advice so I can’t help put add more, for your own good.
I won’t even touch on the ethical issues in regards to the chicken, everyone else has done that but there’s information you should know:
You can’t compare a house chicken to a dog or house cat, they were domesticated in completely different ways, chickens were mostly just contained or encouraged to live around us, while dogs learned that they could live along side us for food. Early dogs and people soon realised they could help each other hunt, and while doing so, both being very emotionally complex animals, formed bonds. Chickens I am afraid do not form these bonds so readily with people. Dogs were dependent on us, and we were in them, chickens can still forage in the wild, but dogs lost their original hunting abilities in replace to working with ours. Dogs can be toilet trained, chickens spontaneously poop all the time - they will begin to smell. Dogs and cats can form bonds with people in replace of other dogs, chickens cannot. We take dogs for walks, this would be difficult for chickens, and if you’d put it in the garden, you may as well put a coop there.
Birds do not carry the same bacteria in their guts as us. Many reptiles and birds often carry salmonella, a type of dangerous type of food poisoning. While this is less common due to vaccines being given to factory hens and sometimes meat birds. I am not sure how available this is from pet shops. Even if the bird is vaccinated, there are still many bacteria which could cause harm our mammalian guts.
I don’t know where you’re based, but here in the UK, we are in the middle of a bird flu poultry lockdown. Chickens must be kept within their coops, not to free range, no shows or auctions. I’ve seen more and more cases in The USA, and even people getting it. At the moment, to me (might just be me being in the UK) it feels like a house party in COVID lockdown. I know it’s pedantic but in a rare case where the chicken you intend to keep inside has bird flu, it seems like a recipe for disaster. It would be very possible that you being inside with the bird could lead to you contracting the virus, and possibly passing it to other wild birds or people. This is very extreme of course. Although, the risk seems to high to me, while i agree that poultry keeping should be for everyone, I am assuming that’s why you want this inside cage, but this could potentially risk the entire hobby.
I don’t know how much I can change your mind, but please can you stop thinking about what you want, rather what the chicken, your health, other pets, other animals, and the entire community wants. Trust me, when the chicken is being loud due to distress and has a massive smell lingering, you will regret it.
