Remember to limit scratch grains and other treats to what they can consume in 10 minutes twice a day. 3 times a day in sub freezing temps. Layers feed should be fed unlimited. Empty and clean feeder every 3 months, monthly in damp or humid weather. GC
There is a big difference between what they can eat in 10 mins if it is scattered around over a large area or if it is put in a pile on the ground or in a container. Personally I think it is better to quantify the amount and say that it should not be more than 10% of their daily ration.
To my mind, it seems to defeat the object feeding a higher protein feed and then giving them a good helping of a lower grade food like scratch. I appreciate we all like to treat our birds and we all know they love scratch but feeding a 16% protein feed and treating them to a handful of mealworms seems like a more sensible tactic! And 16% layer is cheaper and easier to come by.