You need more space, IMO.
Coop is barely big enough for the 4, winter may be tough, let alone adding 2 more.
How did you add them?
Integration is one of the situations that takes more space above and beyond the suggested minimums and you're trying to put 6 birds into a coop barely big enough for 5 -- assuming that those measurements are the actual open floor space and don't include the nestboxes or space occupied by feeders, waterers, etc.
Hens go broody when you don’t want them to… and won’t go broody when you do.
