My pullets (my first chickens ever!) will be 16 weeks on Tuesday. I am currently feeding them Countryside Organics grower feed which instructs to feed until 1st egg OR 16 weeks. I have Orpingtons which I know mature slower than many, so I am wondering if I need to keep them on the grower until their 1st egg or switch them. I am at the point where I need to order more feed and am not sure which one to get. I still have enough grower for about another week. Should I order another 25 lbs of grower, or move on up to the layer? This brand isn't cheap so I wanted to be sure first! Thanks!!