My Mistral Gris go to the butcher in a week. That will be 13 weeks for the first batch, all Roosters. The Hens will go after in a couple of weeks.
I can't be more happy with them. They spend all of their time outside in the sunshine eating grass and the fruit/veggies I give them. They eat way less roaster/finisher pellets than the Cornish Crosses.
Processing weights and dates as follows (only a guideline)
9 weeks cockerels are ~5 - 6 lbs live weight, yield nice 3.5 to 4 lb fryers. Pullets are too small for most purposes.
12 weeks cockerels are 8 to 10 lbs live weight, dress out as 5 to 7.5 lb roasters. Pullets at this age are meaty fryers.
14 weeks cockerels are >10 lbs live, dress out as large roasters. I do not like to keep boys beyond this age. Pullets are 5 to 6.5 lb roasters.
Pullets can be kept a little longer than 14 weeks but the growth rate is slow. They are tender enough for oven roasting through 18 weeks.
Thanks for posting the picture with the growth rates.

So 11 now.