Adding more wort. And oxygen?

[TastyAdventure]

I have a 6 gal batch going. Yeast is WLP002.
Pitched yesterday 12/8 and it has already taken off.
I want to brew another gallon, add heather tips to it, and add 2 gallons of the initial batch to the one with heather in a new fermentor to make a separate 3 gallon batch.
When I add it (planning on tomorrow or the next day) the yeast will have been going for 2-3 Days

1. Should I shake the hell out of the fermentor to give the yeast more oxygen?

2. Should I count on the yeast in suspension from the 2 gallons added, or added more yeast?

 

[RM-MN]

I have a 6 gal batch going. Yeast is WLP002.
Pitched yesterday 12/8 and it has already taken off.
I want to brew another gallon, add heather tips to it, and add 2 gallons of the initial batch to the one with heather in a new fermentor to make a separate 3 gallon batch.
When I add it (planning on tomorrow or the next day) the yeast will have been going for 2-3 Days

1. Should I shake the hell out of the fermentor to give the yeast more oxygen?

2. Should I count on the yeast in suspension from the 2 gallons added, or added more yeast?

1. No. The purpose of aerating is to give the yeast the nutrient that they need for multiplication. Your yeast in the original batch have already done that and you wort will have some oxygen dissolved in it anyway so more isn't needed.

2. By taking beer from the initial batch to add to this second batch you will have added what amounts to a huge starter so you will have plenty of yeast. Adding more would not help.

 

[TastyAdventure]

Thanks!