In general no, you can't over do it...only if they eat them to the exclusion of their feed and that would be rare. I give our girls supplemental protein at least every other day especially when they're laying. They haven't molted yet but they'll need it then as well to help with feather production. They only get the eggs that we find cracked, but I give them yogurt, cheese, meat and cooked beans. They also get lots and lots of greens. All the weeds we pick go in their run, we give them kale, chard, spinach, comfrey and clover. The greens are what contribute to those nice, firm, gold yolks. The ones from the store are pale because those chickens never get anything but processed food (poor things).
Do you have an issue with a lot of predators where you live? Where we are, we mostly have hawks. There are skunks, some coons and foxes in the area, but ours is a residential neighborhood and we have a 6' fence around the back yard and never get any critters in it. We also have 3 dogs, so that probably has a bit to do with it, LOL. Also because of the dogs, we don't let the chickens have the run of the whole back yard, but I wanted them to have access to grass, so we built a portable coop and run. The run is about 20'' high and the frame is made of metal conduit, about 9' x 9'. DH put it together using the conduit and T's and used cable ties to attach the wire, leaving a flap in each quadrant we can open to put in treats, food and water. It's light enough that one person can easily drag it or two can lift and carry it. It's tall enough they can freely walk around in it but is covered to discourage any avian predators. We move the whole set up about every 3 days so they always have fresh grass and it doesn't get wrecked by them scratching on it. They're locked in the coop at night.
Perhaps if you don't have any serious daytime predators, something like this would work for you? It was very easy and would solve the problem with trying to put in permanent fencing.
