Whenever you want really. When they reach the size you are looking for, but most people butcher them between 6 and 10 weeks. Some people keep a cornish cross for a year or more...We have 9 right now that we will probably process around 8 weeks or so depending on their size and such. They are known to have leg issues. If they aren't doing well try not feeding them all the time. Let them run out of food for a bit each day. I feed mine once in the morning and then that is it...if they run out, then they run out. I need to get a larger feeder though so I know they are getting enough to eat in that time...I won't worry as much once they are out of the brooder. They can find their own food if they are super hungry. That will help them with their weight, leg, and heart issues...getting a little exercise every once in awhile. Ours seem to be doing well, but we just got them on the 6th...so it hasn't even been a full month yet and they are really big...at least 3x the size of the laying breed chicks we got at the same time. Sorry for the rambling, long story short process them when you are ready, but don't let them go too long or they might start having some issues...Mine get around fine, but their stomach and breast area is always dirty because they are so low to the ground...
