Our current use of the word is for our near relations, not for the sense of ancestral stock as it is generally used in The Hobbit.  “Kin” comes up more in the book as we get closer to the war for gold, to reasons to divide into “us” and “them”.

• 03.035 my kin.
• 09.018 from their kinsfolk
• 12.072 and where are his kin that dare seek revenge?
• 15.021 that you would send messengers to our kin
• 15.040 The king of friend and kin has need.
• 15.051 you would have paid to our kindred,
• 17.033 We are hastening to our kinsmen
• 17.057 O my kinsfolk!’

“kin, n.1.” OED Online. Oxford University Press, March 2015. Web. 11 May 2015.