Yes, you can freeze cooked chicken after four days in the fridge. However, it is important to note that cooked chicken should not be stored for more than four days as bacteria may begin to grow which could lead to food poisoning if consumed. To maximize safety and quality, the best way to freeze cooked chicken is by preparing it for freezing ahead of time.
It's important to cool down your cooked chicken before packaging it up for storage in the freezer. The safest way to do this is by placing it into shallow containers (this allows the cooled air to reach more surface area), and separating any large portions into smaller sizes so they cool faster. Once cooled, wrap each portion tightly with plastic wrap or foil and place them into an airtight container or zip-top bag labeled with the date frozen (for easy tracking). These measures will help prevent freezer burn on your frozen cooked chicken.
The general rule of thumb for frozen foods like cooked poultry is that they are safe indefinitely if you keep them properly stored at 0°F (-18°C) or lower; however, their quality may suffer over long periods of time from taste/texture changes due to moisture loss. For optimal flavor and texture retention, consume within 3-6 months after storing in a standard home freezer.