I got my first chicken and supplies from Mill Valley Chickens. I read on their website, and the owner's little daughter also told me, that scratch is like potato chips for chickens, and they should not get too much of that treat. Well, I didn't have much of a problem their, because chicken scratch seemed to be one of their least favorite foods.
I've been keeping the chicken scratch in a plastic bag in a galvanized trash can. I'm not careful about the plastic bag and it stays open sometimes. Today I found that the bag was infested with weevils. My chickens ignore ants, so I didn't think they would be interested in weevils. It seems that they can't get enough of the weevils. I left out the bag of scratch, and, for the most part, the chickens ignore the grains and pick out the weevils. The Australorp is the one that eats as many as she can find, but I've also seen the Welsummer and Crested Cream Legbars pecking at them.
chickens can get crop bound from the webs that the weevils leave in the grain.
It is not a good idea to feed weevil infested feed to chickens. The grain is also spoiled and can have a toxin in it--like the ones that died up in Oregon last week.