How much food do chicks need?

I've written before about how much to feed adult chickens.  But what about growing chicks whose needs change almost daily?

One option is to give them free access to an automatic chicken feeder, but then you'll have to worry about attracting rats into the coop and will also end up with lazy chickens who don't forage.  To keep my chicks hunting for bugs (thus paying the least for storebought feed), I give my chicks a certain amount of feed in the morning and then leave them on their own for the rest of the day.

Success With Baby Chicks has a handy table telling how much feed chicks need per day, which I've tweaked a bit and then reproduced here.  These figures assume you're raising heritage breed birds --- Cornish Cross chickens need more food faster --- and that the chicks aren't getting anything from pasture.  Robert Plamondon estimates that it takes about 7.7 pounds of chicken feed to raise a chick to the twelve week age at which I recommend slaughtering heritage broilers.  Here are the specifics:

So, for example, a six week old chick would need around 0.093 pounds of food per day, or a bit more than a third of a cup.  If  you had 14 chicks of that age, you'd need to give them 1.3 pounds of food per day, or about 5 cups.  (A pound of chick feed is roughly equivalent to a quart or four cups.)

Despite being armed with all of this data, I have to admit that I'm pretty sure I fed our first three batches of chicks this year more than they needed.  First of all, they were living on pasture, so the chicks were getting a good amount of their nutrition from insects, worms, and clover.  Second, I actually ended up feeding them more than the recommended amount for birds who don't have access to pasture.  It's just so easy to think your chicks are starving when they come peeping to greet you at the gate, but the truth is that chicks expect treats when they see me, so they scamper over even if their crops are bulging.

The two sets of Black Australorps I raised are a good example of the fact that overfeeding doesn't lead to any extra meat.  At 12 weeks, I'd fed our first batch of australorps 10.79 pounds apiece, and the cockerels dressed out to 1.87 pounds each.  The second batch "ate" 15 pounds of feed apiece, and the cockerels dressed out to 1.76 pounds apiece.  Clearly, the extra feed I gave to the second batch just went to waste.

But my gut tells me that even feeding using the chart above will waste storebought food in when chicks are getting a lot of nutrition from pasture.  Which brings me to a better way of estimating whether you're feeding pastured chicks enough.  With my final batch of chicks for 2011, I've taken to peering at their crops a couple of times a day, and have noticed that even though I'm feeding my chicks only about 80% of their recommended allotment, the chicks' crops are always full.  Now, it's possible that malnourished chicks could still have full crops due to eating things that aren't really food since they're feeling hungry, but our chicks are also perky, with shiny feathers and seemingly stout bodies.  I figure that as long as chicks look healthy and have full crops, they're getting enough (or too much) food, but I won't know for sure until I kill the broilers at 12 weeks and weigh their carcasses.