Ive had 3 clutches of painteds fledge in the last month and another clutchon the way and looking in the main aviary today and saw at least 3 newly fledged BR Double Bars

Not had any sucess with my RFPFS or my Tricoloureds though...not sure why? RFPFS will hatch and then a few days later the chicks are dead

Tir coloureds build and build and lay but never commence serious sitting. Is there omething else I should be doing? They get greens, plenty of nesting material and nesting boxes, they are in a 6x3x2 m aviary with other quiet species.
Any advice?