Yeast on Yeast

http://oz.craftbrewer.org/Library/Methods/Sanders/YummiesForYeast.shtml

Read the bottom part where he recommends throwing in some yeast at the end of the boil to provide food for your working yeast. Anyone ever done this?

You can buy yeast energizers at your LHBS. These often contain some dead yeast, (yeast hulls). This is usually used in wine making, though. My understanding is wort contains enough nutrients to keep the yeast healthy and happy.

He's talking about doing it as a means of adding additional zinc as a nutrient for the yeast. Earlier in the article he seems to indicate that a low level of zinc is mainly a problem for extract brewers.

I imagine its the same as using yeast hull nutrient. I've been thinking about adding some to my beers ever since I brewed my mini-mead. All my beers take two weeks to ferment. Maybe the zinc level is my problem since I am brewing with extracts. I'll try adding a little to my next batch to see if it helps out.