I was thinking something closer to tote size when I thought about how big they'd get and how they like to be sheltered when laying... We did get lots of work done I'm very proud and excited
Indoors we have a folding 4x4 dog kennel for chicken quarantine or hospital use. It needed a nestbox so we found a couple Homz stacking boxes from Walmart (which I haven't seen there lately) with a side entry hole already in it. These Homz come in two sizes and are great. eBay has these available right now for around $18. The small is perfect for bantams but I recommend the larger Homz for large fowl. My friend got several of these for her walk-in coop and stacked them on top of each other to make a row of nestboxes stacked 2 boxes high on a paver stone platform to keep them off the dirt floor. She said her large fowl, i.e., the 7-lb Cuckoo Marans and BCMs use them just fine to lay their eggs. She placed a plywood shelf across the top row of lids to hold down the lids and make poop-cleaning easier. The boxes are very portable to stack or move around and easy to hose down and air dry. I don't need them in my coop space but they are nice inside our indoor kennel. We keep the lid on because the Silkies don't jump up to roost on the lid the way larger breeds will. The box entrance has a nice smooth lip the Silkie can stand on before entering the box. The lip keeps all the straw from being kicked out and keeps the egg from rolling out. If we have invalid Silkies they choose to sleep inside the box for the night.
http://www.homzproducts.com/product/small-stacking-modular-storage-with-lids/
http://www.homzproducts.com/product/large-stacking-modular-storage/
http://www.ebay.com/itm/like/381015220172?rmvSB=true