How long to leave unhatched eggs under a broody when 1 egg has hatched?

[Sionnach Dhu]

Good thing the shop let you buy a single chick! The only real sources around here are Tractor Supply and a local feed store chain (three or four shops total). TS won't sell less than SIX chicks at a time; the feed store won't sell less than four.

Updating on my situation - As of the end of the day yesterday (Tuesday) the first chick is doing fine, but Mama Buff was still insisting on sitting on the remaining 5 eggs; no sounds, movement, or signs of pipping from any of them.
So I'm back to trying to decide if and when I should take those eggs away, for the sake of the existing chick.

 

[Blueoriental]

Oh what a cute little chick! I wanted to buy more but they only let me have one! Someone told me my temp was too high at 38 and the egg shell was too tough for the chick to get out.