A couple days or a few bites of layer isn't enough calcium to do anything to the chicks. But yes all flock or chick starter is the optimum thing to have all the chickens on while young birds are around.
If you have a specific hen that has laying issues that you're concerned about (since you mentioned the vet recommending layer), you can isolate her for a private breakfast. 2-3x a week serve a small bowl (like 1 Tbsp is fine) of wet or fermented feed with oyster shell mixed in. If she does not like chunks of oyster shell, crush it up or use the powdery remnants from bottom of the bag. Should only take her a minute to eat and after that she's free to go. If it works you should see results in a week or two, and you can try reducing it to 1-2x a week and should hopefully continue getting good results.
For the oyster shell, when I do have chicks, to discourage them from eating it I hang it up a bit higher, just so it's not easy for them to reach in and taste it (when they get tall enough to reach, they'll usually try a little, and lose interest).
If you have a specific hen that has laying issues that you're concerned about (since you mentioned the vet recommending layer), you can isolate her for a private breakfast. 2-3x a week serve a small bowl (like 1 Tbsp is fine) of wet or fermented feed with oyster shell mixed in. If she does not like chunks of oyster shell, crush it up or use the powdery remnants from bottom of the bag. Should only take her a minute to eat and after that she's free to go. If it works you should see results in a week or two, and you can try reducing it to 1-2x a week and should hopefully continue getting good results.
For the oyster shell, when I do have chicks, to discourage them from eating it I hang it up a bit higher, just so it's not easy for them to reach in and taste it (when they get tall enough to reach, they'll usually try a little, and lose interest).
