When you keep everything as pets, and won't sell or cull any of them, you can wind up in a mess of misery. Not all birds get along. A lot depends on your space and how your coop/run is set up, but most of us at one time or another will wind up with a bird or birds that do not work in the flock we have.
Chicken math gets most of us, and I can certainly understand wanting to pick up those pretty birds, but chicken math really has to work both ways, as most often the coop/run do NOT change size. If you can't subtract birds, be wary of adding birds.
I keep a flock, but the birds in the flock change. I can admit that some birds I like better than others. I keep those birds, and let others go. A happy flock can only be arranged by controlling who is in the flock. Wishing they would all be nice won't work.
SO measure your coop, count your birds, and go into this knowing, if I take these birds, I might have to get rid of others, or just keep the birds you have.
Mrs K