I'm also planning on having an indoor bantam cochin but all the mean people in this forum are against it because they have massive outdoor backyards.
I can promise you that no one is trying to be mean. We are all discouraging this because it is not a good choice and would be cruel to the chicken. Chickens are flock animals and do not do well by themselves. They need to be in a flock with other chickens to be happy. They also need to outside as their natural behaviors are scratching and digging for insects and such as they are foragers.
Chickens also smell in close quarters. My brooder is inside so for 6-8 weeks my chicks are indoors. No matter how often I clean the brooder the garage still smells and so do the chickens. This is a larger garage with windows and doors open all day and night with lots of ventilation. If it still smells there then no doubt a house is gonna smell terrible with chickens inside living there full time especially with the urea in their poop. Not only that but they produce so much dust.
We all want what is best for the health and welfare of chickens. This means that yes, we will highly discourage keeping chickens inside as a full time pet as it is cruel to the chickens and not hygienic to the humans living in the house. You don't need a massive outdoor backyard to have chickens. You can make do with a small yard as long as they are living outside in a coop full time and not indoors.