My chickens are getting close to their date with destiny, but I'm not sure just how far to let them go. The "slow Cornish" are 8 weeks old and the Buff Orpingtons are 10. The Cornys weigh about 4.5-5 lbs. I haven't weight the BOs - they are about a third less than the Cornys. Several of the Corny's have developed misshapen feet - the toes bend and curl backwards. I guess that's one of their genetic pitfalls? They get around well though, so I haven't worried about it. Everyone is in a tractor during the day and in the coop at night. I let them out to range for a few hours a day. They are very active. I thought I read somewhere that 5 lbs live weight is good for harvesting, but would like to hear other thoughts. Thanks!