My jersey giant's won't go into the nest boxes. I am using those stacking pet food conatiners with the door removed. it works perfectly for everyone else. I'd love to see what other giant owners use.
This is what I use. I got them from Lowe's for abour $8. I have 4 and they work great. All my girls are large breeds. I have a 12lb. Blue Laced Red Wyandotte and she can fit just fine. They come in different sizes. This is the 3rd largest one. They are stackable but I have them side by side with old fiberglass lunch trays for the top.