I would do it when the eggs start to hatch. Some broody hens sit for a couple of days after and some dont wait as long. I wouldnt risk the eggs being abandoned, especially if you dont own an incubator. Make sure to stick the chicks under at night.
Yep, I would think its just a glitch. Happens once in a while when a hen runs out of "ink". It happens more with older hens as well. Since blue and green eggs have a blue undercoat, its one of your brown layers.
Permethrin dust and spray, dog crates, a dewormer (Valbezen is good), dog pads, gloves, Monistat 7, hydrogen peroxide, masks, extra syringes, a bottle of corid, electrolytes, blow dryer, scissors, calcium citrate, and Vaseline.
EEs usually lay green and blue. Silkies, Turkens, cochins, and barred rocks lay cream/brown. I would guess the sexlink lays the darker browns. Although its better to catch them in the act. All your breeds except your EEs are not supposed to lay blue and green though.