Is it not allowed to have two kitchens at home?

Of course, if the main house has a reasonable structure, it can have two kitchens. The general structure of the kitchen requires gas, water, electricity, and smoke exhaust pipes.

Kitchen refers to a room in which food can be prepared and cooked. A modern kitchen usually has equipment including stoves (gas stoves, electric stoves, microwaves or ovens), sinks (dishwashers) sink or dishwasher) and food storage equipment (e.g. refrigerator).