06:45 F rises from brooding the hawklets, retrieves a prey (field mouse) item and starts feeding both hawklets. The older hawklet is cropped up from an earlier feeding. It is very easy now to see the development of about 1/2" long pin feathering on the older hawklets wings and tail area. The younger hawklet received a decent feeding but wasn't quite cropped up.
07:01 F jumps with prey to 9 ledge then flies (with prey) toward 9
I think it is possible that there is some internal or genetic situation causing the younger hawklet to ingest less food or process it to maintain a normal growth rate. "Lazarus" is less than half the size of the older hawklet. At fledging age a male would be about 20% - 25% smaller. In falconry terms males are often referred to as a "tiercel's" or "tercel" (French for 1/3) because of their smaller size. Reverse sexual dimorphism is the scientific term for the males of a species being smaller than the females. (It should be noted though that not all males are smaller than all females in all cases or all species. Example: A male Bald Eagle from Alaska may be larger that some females from Florida. Also in the Andean Condor the males are larger than the females.
Coinciding with these events, the level of aggression from the older hawklet has subsided greatly, if not completely. It will be interesting to see if the youngster can put on a growth spurt in the coming weeks. Nutrition is paramount for normal bone and feather growth. The quality of prey items brought to the nest has been more than enough to meet the nutritional needs but the quantity ingested by the younger in the past week, in my opinion, is falling short of the number of calories needed for normal development.
If you continue to think the way you've always thought then you will continue to get what you've always got, is that enough?