I raised Cornish for the first time last fall and at 8 weeks dressed my birds were the same 3 to 5 lbs. I said if I do it again I’d keep em an extra week maybe only order roosters. I’d seen the YouTubers that went 8 weeks and their birds were over 5 lbs. wonder now if that was the start of the dwarf birds. Basically mine averaged 4.5 lbs at 8 weeks. Feeding the quality feed and all. I ordered mine from meyers but they were direct shipped from the hatchery.