rescue chi

Question
I have just acquired a rescue chihuahua around 3 years of age who was raised in a small pen.  I'm trying to socialize him and work him into the household, but my older (4 1/2 years old) and larger chi keeps trying to put the newbie in his place - which causes the younger chi to cower and stay in his bed.  It's been not quite a week and I thought the older chi would stop his aggressive behavior by now.  How much longer do you think the older chi will be putting the younger one in his place?  (there has been no violence or nipping...just 'charging' and the occasion bark on the older one's part.)  Any help with this problem would be greatly appreciated.  BTW, the two chihuahuas are the only animals I have.  

Answer
It usualy just takes some time,and if there not really hurting each other,I wouldn't worry much about it-they will sort each other out

But never leave them alone together for at least a year,just in case put them in seperate room or in crates when you are gone