We have given our chicks their health check, and believe we have a male 14 and a female 15, given their measurements.
For those who are interested, their vital statistics are:
White 14 Right leg BTO ring number 1447452 Wing 300mm Tail 152mm Weight 1450g
White 15 Right leg BTO ring number 1447453 Wing 340mm Tail 154mm Weight 1670g
Here they are safely back in the nest with KL attending.