digitS' :
Your 4, 9 month-old pullets should be eating 16 ounces to 32 ounces of feed each day, depending on breed (and 32 ounces is probably for the very largest chickens around).
The scratch I buy weighs 4 ounces per cup.
If they are a light-weight breed, a cup of that scratch would amount to 25% of their 16 ounce rations.
"A general rule of thumb is to feed
only as much scratch as the chickens can consume in about 20 minutes, or about 10 to 15 percent of their total daily food consumption. . . . Table scraps and greens . . . The same rule applies here: the total supplementation of scratch and table scraps
should be no more than can be cleaned up in about 20 minutes."
Oregon State University, How to feed . . .
I hope that helps. It's very easy to give them more scratch and scraps than probably they should be getting. It has a lot to do with their enthusiasm for more, more, more . . . My birds eat about one-third more feed now than they did when it was still warm about 3 months ago. Daytime temperatures are not rising above freezing.
Steve
If I left mine (24 pullets) with a bag of scratch, I swear they would go thru 1/2 of a 50# bag in 20 min. As far as treats go, I take a big bowl full and it disappears in a minute! I can't imagine what they could eat in 20 min!
I put a cabbage out there and it disappeared like a sacrificial cow in a river full of piranhas!
A sweet potato goes even faster.