I keep big pans in the coops and out in the yards with laying crumbles, pellets and scratch in them. Mainly because I have chickens in sizes from bantams to giants, not to mention ducks. The large pans with high sides keeps them from scratching food over on the ground as much. I do keep a 3-4 foot ply wood disc (Not pressure treated) where I put out scratch (did I mention mine free range in the fenced yards). It keeps it out of the grass and if it gets spoiled by rain it gets turned into the compost heap. Not to mention in the summer crickets love to hide under it, so flipping once a week is a chicken cricket hunt bonanza.
If it is going to rain I put up the big umbrella (table size 2-3 foot off the ground) over the disc, if they call for high winds then I don't put out the umbrella or scratch on the disc. I have several tarped shade areas here and there with food/scratch and water under them.
I find they do not over eat in the winter or summer. Summer you can cut the feed amount by half or more here and the scratch even more.
As mentioned earlier I will get mobbed anytime I am in the area. You would think these kids were starving, they are just masters at acting like they are to con a treat or two. Never try to eat a sandwich in the chicken yards. My one rooster can jump as high as your mouth to grab your lunch !
I try to stay away from giving the chickens or ducks any white bread, it is only empty calories. But if you put it under your mulch pile the worms love it.