We were never intended to see more than that; but as time went on... Here are the details. (https://metv.com/stories/originally-we-were-never-meant-to-see-more-than-the-back-of-alan-bradys-head-on-the-dick-van-dyke-show)

Weirdly, after Season 2 Pickles becomes an unseen character, just the other end of phone calls and the subject of funny stories.