It's way to early to tell the colours of your chicks.
In your brooder, rather than worry about the actual temperature, let the chicks tell you if the temperature is right. From what I can see, your chicks are saying they're comfortable. If they're cold, they'll huddle together. If they're hot, they'll be anywhere but under the heat lamp and often be stretched out.
I would remove everything but the feeders and waterers for the first week. They are very good at getting under things and dying. You want to be able to see them until they gain a bit of survival sense.
You're making me want to get buttons again! I found homes for all of mine before I moved.