I suppose it won't hurt to wait an additional week, they seem comfortable in the chicken tractor and the fan is keeping them cool in this heat. They also appear to be eating at a normal rate and they're drinking more than 7 gallons of water a day (wow!). I could certainly use that time to catch up on some harvesting equipment building projects that were put on the back burner while I spent time predator proofing the property last week.
If nothing else it gives me a good idea of the quality check on roasters from Meyer before I buy a larger quantity of birds.
Update: literally 3 days later they had some kind of growing spurt - LOL! It was the craziest thing... now I'm not prepared to do the harvest this weekend and it's supposed to storm for 3 days anyway so it'll have to wait until next. Of course, the July 17th weekend it's supposed to be 100 degree's. I think I'd rather be out there in the pouring rain!