Walmart dishwashing basins (sterlite) under $3... works well for me and my EE's. Not sure of exact dimensions think its about 14" X 22" maybe 8" deep. My coop has nest boxes built in with one of these in each of the 3. The way the coop is built it gives them a sense of security with dividers between the 3 nests. I have 6 hens and for whatever chicken reason they all want to use the same nest.