Unless you really like wasting feed, don't mix the scratch in their layer pellets. You might want to cut out the scratch altogether. Your birds are most likely eating the scratch and pitching the pellets. This will lead to all sorts of nutritional deficiencies.
I ferment my feed, and use scratch only as black mail when I need to get them into the coop in a hurry, and sometimes when I need them to give a particular area a good deep tilling.
Also, pay attention to mill dates when you buy feed. Feed older than 6 weeks is rapidly loosing nutrients.
PM to follow.