When to proces heritage turkeys?

[Hardemans]

I have a flock of dirrerent aged heritage turkeys. At what the best age to process those birds? I have raised the broad breasted variety and they were good at 5 months. I know heritage take much longer.

Do they get tough as they get older? Mine free range so i would likely have to pen some to fatten them up prior to processing.

Thanks in advance for any advice.