Last year we hatched off two full-sibling broods where I kept come pullets from each. First brood hatched Easter Sunday 2019 and second hatched in late August. Pullets from the two broods came in to lay at about the same time in Early March. Egg size differed obviously between the two groups. Older group produced eggs that were nearly what outright hens produce when a year plus old which was close to 60 g each. The younger group produced eggs that where in the upper 30's to low 40's. The chicks produced by the younger pullets started off at best 2/3's the weight of their cousins by mothers and half-siblings by father. I am having a little trouble with some of the smaller hatched chicks that cannot take the cool weather like the larger chicks. The problem does not appear to be related to mothering ability of younger pullets post-hatch as they are rearing chicks from larger eggs just fine.