What I'd Like to Know: Age Distribution of Small Farms

From Farm Policy, this quote got me wondering:

The FT article concluded by stating that, “Tom Sell, a farm industry lobbyist in Washington, says US farmers receive relatively less support than their peers in other countries. He adds that removing financial aid will hurt smaller, family farms and accelerate the move to industrialised [sic], large-scale farming.

This follows a discussion of how the biggest farms produce most of the crops.

But what I'd like to know, is how the age distribution of farmers relates to the size distribution of farms.  It's probably available in some ERS study, but I'm lazy today, having just returned from working in the garden for the first time.  Why would I like to know this?

My suspicion is there's two types of old farmers, those with children who are going to go into farming (like John Phipps) and those who aren't (like my dad).  The first category and the young farmers (not many of those) are forward-looking, wanting to expand, buying up land when they have the chance, looking at the future, etc. etc.  The second category is probably conservative, without the drive or incentive to take a lot of chances in order to expand.  My bet is there's a big difference in the size/intensity of the farming operations of the first category and the second. If my stereotypes have some truth to them, we might well be overestimating the importance of a safety net for the smaller farms. I'd also hazard the guess that the first category is more indebted than the second, so the second can coast to retirement by mortgaging or selling land.

I may well be wrong; it's always dangerous to traffic in stereotypes and examples which readily come to mind, but then life is dangerous.