Usually it's 9 to 10 weeks but with mountain goats it's only 7 weeks because they have a thicker coat of fur which hastens the hatching process. Cheers!
My own personal feeling is that it depends partly on the temperature.... you have to maintain warmth and humidity.. oh and be sure to turn them regularly... if you, whoops I mean your friend, gets too bored sitting on them you could try putting them into an incubator.
It seems back in days of yore, the early ancestors of goats were egg-laying critters as evident by this fossil uncovered in the Ukraine
This post was edited by Benedict Arnold at April 19, 2017 2:25 PM MDT