16% layer...with oyster shells mixed in by mill?
Layer crumble is probably made mostly from corn,
look at the ingredient list to see,
so not good to mix more in as it will reduce overall protein and other nutrient content.
Layer feed should always be available.
Corn and scratch grains given...
A move can cause a cessation of lay due to stress of a new environment...
....and a different diet.
Mill scratch mixed with more corn is probably low in nutrients....
....and vitamins/minerals/amino acids.
Put them on a good layer ration,
with scratch and corn as an occasional 'treat',
and...
Ayup...keep treats to a minimum.
The heat can slow them down too.
What breeds do you have and how old are they?
Some slow down their second year of laying.