Is your coop big enough to where you could keep them in for two days and see what happens? Sometimes they don't lay very regularly at first, but RIR's are generally very good layers......
Could something be eating the eggs? Chickens will eat their own eggs sometimes. Also the beloved family dog might eat them.
Could a neighbor be taking them? (A friend had a neighbor stealing eggs! I couldn't believe it!)
Whenever I have pullets that are about to lay, (now I have a large hen house with an attached chicken run), I will keep them in the coop/run for a while, until they get into the habit of laying in the nest boxes.
My girls have been laying for quite some time now, and one day, I left them out from morning until dark, and I only got 3 eggs. It was a little experiment I did. Bad outcome. Now they only get to free range after 5pm, when I get home from work. Maybe your hens have found a really cozy spot under the porch or a bush or behind a bale of hay......
Keep me posted!
Sharon