Secondary fermentation/carboy question

[-Liam-]

I've been considering brewing a pretty big Chocolate cherry stout soon and I see that if I wanted to add cherry juice, I would need to do this in a secondary fermenter. I have never transferred to a secondary before and if it's a case that I do this time, I've only got a 6 gallon carboy to transfer too. I'm worried about the extra head space in the secondary and that the stout will get oxygenated. So, what are my options? Can I just add the Cherry juice and cocoa nibs to the primary once the initial fermentation finishes? If so, how long more can I leave it in the primary (assuming an initial fermentation period of 2 weeks)

 

[Hoosierbrewer]

You can leave it for awhile in the primary. I have left for over a month with a stout. I had one I bottled too soon and whoa nelly did I have gushers.

As far as secondary, I would not worry about oxygenation if you have it capped. The yeast may still be working. I chill my secondary about a week before I want to keg or bottle. It helps clear the beer

 

[Hoosierbrewer]

I would put cherries in secondary. Not sure about cocoa nibs. I would probably add last 5-10 minutes of boil. If you introduce cherries then make sure you bring their temp up to kill any wild yeast or bacteria.

 

[-Liam-]

So what are the reason(s) for not just putting the cherry juice into the primary?