It would be neat if the writers had already presented the idea of Miss Petunia's return in Season 3 as a multi-episode subplot. Just saying this because I'm horrible at pitching ideas and they wouldn't take outside ideas anyways.
It would start with Jerold at some point hand-delivering Miss Petunia to Shelter 17, and much to Lucky's chagrin, she's looks as pregnant as before. A year, more or less, has passed since Miss Petunia shuttled herself to the that pound, and Jerold tells McLeish that he was so happy with the care his dog received the last time she was there, he wants McLeish to daysit Miss Petunia until she has her puppies. Jerold states his willingness to pay whatever boarding, feeding, and miscellaneous expenses necessary to keep her happy and healthy, which actually means catered to and coddled over. Like McLeish, the Pound Puppies think Miss Petunia had only a week or so to go before she has her pups, but it's actually a month or so. This isn't known by them at first, but when every time Jerold drops her off, she's bigger in the midsection, hungrier, and needier, an explanation is demanded. By then, Jerold has brought Miss Petunia for another check up at Dr. Trudy's, so Jerold proudly tells McLeish that there's at least eighteen pups inside Miss Petunia. Eighteen is the number that Shauna had in the original Pound Puppies episode "Snowbound Pound".
In the beginning Miss Petunia is reluctant to and apologetic for asking for things and sorry for putting everyone in this position. Gradually, however, she becomes more and more accustomed to her dependency, and eventually expectant of Olaf and McLeish's aid in even the most minor of things. Olaf is carting Miss Petunia around for her walks, and she's snacking on whatever Olaf brings in for himself as well as the reserves for the other dogs. As Miss Petunia's demeanor changes and she becomes higher and higher maintenance, the Pound Puppies are ostracizing her more and more in response. As they watch Olaf waiting on Miss Petunia maw and paw, though a perfect distraction for the Pound Puppies to do their puppy placement work, Lucky comments that this is exactly why the shelters don't deal with pregnant dogs. I don't know if Lucky knew Miss Petunia was pregnant or thought her some chow-hound, but he gave Miss Petunia the same "problem" assessment as McLeish when she was first being brought in.
Somewhere along the line, the notion of getting Miss Petunia spayed is brought up to Jerold and Miss Petunia by McLeish and the Pound Puppies, respectively. The owner and pet team both have reservations with the idea, each thinking the other is happier when she's like this, and whole-heartedly stating their faith in Shelter 17 being the best pound anywhere, which will undoubtedly find placement for no matter how many pups she has, so what's the big deal. Jerold adds to McLeish that he's paying handsomely for Miss Petunia's upkeep, and McLeish will get that much extra recouped for each healthy pup that gets sold off. McLeish mutters he's not running a puppy mill, and isn't really big on the notion of having to periodically care for one either. He would back out though because from what I've gathered, he's yet to or rarely actually places a dog or pup himself and so must be working quite far in the red in financing the shelter.
Eventually, maybe in the season finally, Miss Petunia has her 18 or so (25 maybe for the extreme, like She's-the-Fastest from the Simpsons, though the real life record is 23) puppies. As their obligated to do, the Pound Puppies make an effort to match them to new owners, but at the end of the day, only four on top whatever other pup(s) that were brought in, get adopted. Miss Petunia is once again extremely apologetic for the trouble she's put everyone through, and Jerold and her leave with the non-adopted puppies. As they leave, Lucky concedes that given enough time and resources the Pound Puppies would have very likely found good matches for all those pups, as they'd had harder challenges before ("The General"), but sometimes failure is necessary for a bit of touch love.
As such, Jerold takes the puppies over to Dr. Trudy for their shots and when spaying Miss Petunia is brought up again, Jerold and Miss Petunia both agree it might be for the best.
So, what do you think? Comments. Critiques.