Balancing Feed With Other Food Question

[Awestruck]

I learned recently that an adult chicken eats 1/3 pound of feed a day. I calculated that for my 9 chickens and that a bag would last us about 11 days (the bags is about 35 pounds). A bag actually lasts me about 3 weeks.
My question is, does a chicken eat 1/3 of a pound each day if the chicken doesn't get anything else to eat? What about chickens that are in the yard and eat grass and bugs? Do they still need 1/3 pound feed per chicken each day, or would the grass and plants they eat supply some of that requirement for food?
Do some people just rely on grass and bugs as the chickens primary source of food? And if so, do they skip the feed altogether?
I seemed to be confused on this.
Thanks for all the help here.

 

[Kiki]

Read this:
http://articles.extension.org/pages/69065/feeding-chickens-for-egg-production
May clear some things up for ya.

 

[wvchics]

I personally provide my chickens with as much feed as they want, but I also let them eat whatever they find. They are all happy and healthy. Although I must admit my main concern is making them that way, and I just take what they give in return. I don't use any special tricks for faster growth or production. Everyone is different though.

 

[jennyf]

I thought I had read about 1/4 pound per chicken. Suspect there will be some major seasonal variation (no bugs in winter, burning more calories to stay warm, no greens) and spring-fall when they can supplement.

 

[Awestruck]

Thanks for the insights.

 

[Kiki]

Thanks for the insights.

Did you get a good enough answer?

 

[wvchics]

No problem hope it helped.

 

[Awestruck]

Yes, thank you for the answers you wrote.