I wish like crazy we could know up front where you are from because it would give us a hint of how much biomass you have for your chickens.
For example, you will notice my profile states I live in the southern Rockies in Colorado and most folks will be able to determine that my environment is extremely arid and the soil too rocky to support the biomass to adequately supply nutrition to my chickens.
Likewise, a person that states they are from equatorial Africa would have the sort of lush biomass most of us from desert environments would envy. Chickens is such a lush environment can get along very well on foraging alone.
Sermon over. If you wish for your chickens to use a feeder that is located inside their run, you need to habituate them to using it before you let them roam. Once they know it's there, they will return to it to satisfy what free ranging lacks in nutrition.
However, if you live in a semi-tropical climate such as south Florida or a tropical one such as Hawaii, I wouldn't expect chickens to bother much with a feeder no matter where it's located.