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.