there we see the preengland/oilgland/uropygial gland
(the uropygial gland produces oils that a bird squeezes from it in order to apply to its feathers, thereby waterproofing them. Uropygial comes from Greek words meaning “rump” and pygostyle from the Greek meaning “rump pillar.”)
Chicks will be today 76/76 days old (hatching: 01.05, 01.05, 03.05 - perished 18 days old, 04.05 - died 5 days old: parental infanticide/brood reduction) The chicks become capable of flight at the age of 68–72 days (maiden flight). Starting a flight depend on more factors.