this is my experience with a similar problem & also Jedjackson could be right , but i have cured a lot of things with good nutrition, so here is my story = i bought a year old hen from a breeder, a top laying breed like your RIR , i put her into quarantine for months , just to make sure she was well and to keep my flock safe from any unknown illnesses she could have , she never laid an egg for all that time, then she would lay an egg every once in a wile , this went on since 2014 when i got her at 1 year old , then last spring i noticed she was laying more eggs then her usual, and it was not until this past august that i noticed she was eating the cat food i leave out for my new cat, then this hen starts laying an egg every other day or so,why would that happen...? the only thing i could think of is its got to be the cat food..? she may have had a nutritional problem all along, and i feed my flock well sprouted barley & a good quality layer feed & hi quality vitamins some hard boiled egg & leftovers & what ever else i have around fruits & veggies and they free range , so you never know, but one thing it cant hurt to try a bit of dry cat food & you could also try a bit of mashed up hard boiled egg in her food and see what happens..? my other hens never ate the cats food so when i saw her eating cat food it was a bit unusual to me, and since she started eating cat food , she starts laying eggs, so i guess it worth a try,