Help! My lovebirds have these weird bright spots on their heads

[Carolina123]

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These three siblings were born in January, so they're about 5 months old now. We had to remove them from their mother because they were getting plucked by her. You can see it in the green bird that his head is all funky, he was half bald for many months. I don't know if it's their colours changing or something like that, but my parents say that it's a normal thing, yet I can't find any pictures of birds looking like this online. Does anyone know what's wrong and if this is normal? Is it just the plucked parts already having been grown as adult feathers? Thank you and have a good day!

 

[Iasonas]

My lovebird has this too and didn't always have it. I got it when it was 3 months old and didn't have it now its 5 month old and he has it on its head and a few in its wing so it's a normal thing