I've been doing it for years with no ill effects. I never switch feeds except for sometimes I'll give them chick starter in the first week...if I feel like it or get around to it...and that still is mixed with layer mash. Years upon years, actually, and my flock never have illness, lay well into their older years and never miss a beat.
One thing to note...my birds also free range, get tons of exercise, only get fed once per day and do not depend entirely on commercial feeds for their main diet, so that will be a consideration.
Free ranging is the bomb.