I'm not clear on why you don't feed layer feed? I thought it was supposed to have good protein. What do you feed your hens then?She won't become malnourished if she's on a complete feed appropriate for chickens.
Put out a container of oyster shell. I don't and never have fed layer mix. It is too low in protein IMO and I don't like having my flock on such a high level of calcium at all times, even when it is not needed by their bodies.