Of course Green Acres was before All In The Family, and I was under 10 years old throughout the 60s, and furthermore I often did not understand the plots of each episode of Green Acres, but I recall that a pre-teen girl was cast as a regular character in the show at least during the later seasons.
I had heard that whenever a TV show has been on the air for a certain amount of time, new characters are brought in and when it is a child, it often means that the show has Jumped The Shark.

Sure, Green Acres aired before the term was invented, but I am wondering if the show's producers were trying to attract a younger audience, or try to find ways to make scenarios for funny episodes with a child as impetus.

I think that the little girl in Green Acres visited Eddie Albert and Za Za Gabor's characters and stayed.

the last two episodes of GREEN ACRES were "back-door pilots".

I never thought about it that way,
since those five episodes were not that memorable to me.
I like all of the episodes in the series,some episodes were better then others.

EVA Gabor co-starred, not Zsa Zsa.

Of course Green Acres was before All In The Family, and I was under 10 years old throughout the 60s, and furthermore I often did not understand the plots of each episode of Green Acres, but I recall that a pre-teen girl was cast as a regular character in the show at least during the later seasons.
I had heard that whenever a TV show has been on the air for a certain amount of time, new characters are brought in and when it is a child, it often means that the show has Jumped The Shark.

Sure, Green Acres aired before the term was invented, but I am wondering if the show's producers were trying to attract a younger audience, or try to find ways to make scenarios for funny episodes with a child as impetus.

I think that the little girl in Green Acres visited Eddie Albert and Za Za Gabor's characters and stayed.the stars were Eddie Albert & EVA Gabor not Zsa Zsa.

For whatever reason they brought the kids in, it was definitely a strange, uncharacteristic move, and if nothing else an interesting story arc. Personally that string of episodes didn't bother me at all and it was a unique look at a different, more serious side of Oliver and Lisa's characters.

I was going to say "The City Kids" was a step in a more realistic direction, but then I remembered this is the same episode with Lisa's banana jam and an invisible man driving Haney's truck... Apparently just another day in Hooterville regardless of the guests.

I'd say this was definitely not a shark jumping moment, because again, it was just a five-episode stay for Lori at the start of the season. If she had stayed longer, I agree, that would have upset the dynamic of the show pretty severely and I'm not sure what would have happened.

Way back then, I was too young to really comprehend the greater issue of a TV show losing its originality even though I could see that after a while, characters change and sometimes new ones are brought in at least for a while.

Since all TV shows are advertised as being funny, or interesting in some other way, I wondered why I did not enjoy certain shows or think of the shows as a great viewing experience as the "trailers " would say the shows will be.

As a kid myself, I even liked seeing a child character brought into a TV show that had all adult characters in it, at least for some episodes. I often felt that only kids TV shows had kids in them and those were so obviously juvenile.

Back then,I thought that the Green Acres episodes with "Lori" were fun and
made some of the episodes easier to understand.

Then again, back then it was not yet a very huge move of the TV producers or executives to "attract a new audience" not like it became in the 1970s with bringing in younger characters practically in every popular TV show even if there were already kid characters in those shows such as The Brady Bunch and One Day At A Time, and The Partridge Family.

The city kids being added may have had to do with the fact that the show was moved to an earlier time slot (Tuesday's at 8pm). The ratings on the show were declining (in season 5 the show dropped from the top 30 for the first time in its run), so I guess if the character of Lori clicked she might have been added to the cast.

One thing to add, CBS was moving in a different direction, Jackie Gleason, Red Skelton and Petticoat Junction were cancelled at the end of the 69-70 season, the Green Acres scripts for the beginning of 70-71 may have already been developed when those shows were not renewed, the handwriting being clearly on the wall adding Lori may have been 86'd.