I am assuming the chicks have fully fledged and are not food dependent on the parents anymore. In the wild, the chicks would leave the parents, and so there would be what is perceived by the male, direct competition.
It is recommended you remove the chicks from the parent birds due to this competition and territoriality factor.
Answered by Cathy Johnson-Delaney, DVM, Dipl. ABVP-Avian Practice, Dipl. ABVP-Exotic Companion Mammals.
Becca
Chelsea @ TWFA
tauridvm
TWFA Guest Writer
The White Finch Aviary 
What if the babies are still dependent on the parents? Not quite four weeks yet? They are starting to copy the older boy’s behaviour…..
Hey there! If you’re trying to encourage your babies to wean, giving them black oily seeds that are easier to open is helpful – like Nyger, Thistle, Rape, etc. LadyGouldian.com has a Tonic Seed Mix for sale with all black oily seeds. Sprouted seed is also easier for them to open since part of the work is already done for them, and sprouts are a nutritious snack. Spray millet or diced hardboiled egg always works great for me also. The high quality spray millet like California Golden is thick, bushy, and nicely dried out making it easier to open for babies as well.