We got ours as day old 6 weeks ago. It was so hot that week. Lowest temp was 79 and humid for the first 5 days. We did not use a heat lamp on them even as day olds. Very different from most but it was just too hot & humid. For the first week and a half we raised them in this pen I built. We raised them free range with feed available 24/7 for their short stay. We used Dumor 20% protein entirely. 5 birds went through 50 lbs in 45 days. This was shared with one turkey, 2 guineas and seven other pullets. THAT IS GREAT FEED RATIO. Best I ever had. That put my feed cost at around $5 per Cornish X and of course those numbers are askew as it was shared with the others. At 4 weeks (approx) they looked like this... Today (47 days) we processed two males and one female. 5.1, 5.2, 5.3 lbs fully dressed with NO skin (necks, gizzards, livers, hearts, and chicken feet weighed 2.25lbs) on them. Not bad. We are very happy with these birds time after time. Great breast meat. We will give the other two another week to put on more weight.