Art can be a potent vehicle to convey a vegan message. But there's a level of difficulty, since this particular message is based on disturbing facts: Namely, a large percentage of humans are engaging in frivolous, unnecessary acts that cause the violent deaths of millions of animal persons every day. This message doesn't go down as easy as, say, "There's No Place Like Home" or "Stay Away From Clowns in Sewers."

So how do vegan artists either repackage their central point or sweeten it enough to get people to take it in and consider it?

This played out famously in the controversy over Ruby Roth's book Vegan Is Love (North Atlantic Books, 2012): Roth was attacked for including messaging and facts "unsuitable" for young readers. On the other end of the scale is Sue Coe, whose books such as the recent The Animals' Vegan Manifesto (OR Books, 2017) use all the tools of artistic composition and expression to fearlessly, purposely lay bare how savagely disturbing is the reality of farming animals.

Philadelphia will get a live, up-close look at this phenomenon in action tomorrow night as Michael Harren's The Animal Show rolls into town to play the Rotunda (full info below). He's in good company in the Philadelphia region, where several noteworthy artists have made their mark while navigating this issue.

Julia Barcalow of West Chester this year authored That's Not My Momma's Milk! (Vegan Publishers), a board book with the simplest of plots: Each pair of pages shows an animal mother and child nursing, with the phrase "That's not my momma's milk!" and a sentence identifying the animal mother, with the next page specifying that "her milk belongs to her [offspring]," depending on the species.

On her blog, Barcalow explained that after having a baby, "the more I researched and experienced life with my little one, the more motivated I became to write a book for children her age that supported and normalized the beauty of breastfeeding and the compassion of living a vegan life."

With a text that consists of simply declared facts, the task of appealing to parents and children alike fell to illustrator Kayleigh Castle, whose gently cartoonish animal characters are instantly adorable. With all this positivity, the negative message - that mothers' milk is daily being stolen from animal infants as those babies are permanently separated from their mothers - is turned inside out, implying a world (whether fantasy or future) where actions toward mammal mothers and children reflect truth and logic.

Obviously, those are not the drivers behind milk-drinking: A large proportion of adults are clueless as to how milk and motherhood intersect. Reflecting the normal standard, Castle said that "I grew up with the concept that cows just automatically give milk." She added that working on this book "was really therapeutic for me, like speaking to a younger version of myself. I wish I'd had that sense of clarity."

Clarity about animals' value is a goal of vegan art, though not of mainstream culture, and Philly author Alexandra Fields says she was clear early on that something was off: "From the time I was very young, I didn't like the idea of eating animals," though it was only after learning about the intensive eco-impact of meat and dairy, via Howard Lyman's Mad Cowboy, that she took the plunge and went vegan. She recently published a children's story (for already-reading-age kids) about a cow who is awakened to the horrors of her situation and escapes into the wild.

Emma, issued this summer by Fields' own EcoLit press, tackles the sensitive-info question head on: As a calf, the protagonist watches her mother dragged away to be trucked to the slaughterhouse. And though Fields doesn't use that last word, she acknowledges that "I pushed it further than some people wanted me to." In fact, she's had stores turn down the finished product for being "too strong, because of the 'Vegan agenda,'" she said, but she has no regrets.

"First of all, her mom getting taken away, I included that because it's pivotal to me. I think it's important for children to understand that we are taking animals and killing them. I'm doing this with purpose in mind." On the other hand, "I'm not going to have blood" - and indeed even the most provocative scenes are handled gently and with subtlety to meet kids where they're at rather than traumatizing them with the most harrowing, unvarnished truths.

Speaking of truth, Sarah Clemency's Becoming Vegan, a one-act musical that premiered in September as part of the Fringe Festival, focuses not so much on the truth behind the animal-food fairy tales we're taught, but being true to oneself, and especially to one's significant other.

Her musical -- "my first," she noted, though she'd had plenty of experience writing cabaret songs for her musical duo Catherine & Sarah -- tracks the relationship of two women, one of whom is vegan and the other who isn't but is initially assumed to be by her girlfriend. The jaunty, high-energy show showcases food issues from people's everyday life rather than making a statement about animals, but ends up, with the help of dancing fruits and vegetables, making the choice to live vegan attractive and fun.

"The main message for me is that we shouldn't lie about it," Clemency said. Did she find herself policing the tone? "Yeah, I wanted to watch out for moments that would get too serious," she replied. "I'm not trying to make people feel guilty." On the other hand, it's possible to get too light and silly: Of a scene near the end where the nonvegan wrestles with her animal-food addictions, Clemency relates that early on, "when the man comes out dressed like cheese ... people were laughing too hard to hear the dialogue."

Clemency is not vegan herself, but was partially inspired to write the show as a vehicle for her longtime friend Lizzie Spellman, who played AJ, the already-vegan love interest. She did offer that when writing the show "I did go for a month without eating meat. It wasn't hard, but I went to a restaurant and noticed that there were not that many options" for vegans. She concludes that going vegan is "a goal that's in my reach -- maybe still a little far away, but within my reach."

Megan Cavallari has already reached many artistic milestones, having moved from her native Philly to Hollywood, where she makes her living as a film composer, and having gone vegan six years ago. She's worked with and learned from icons like Jerry Goldsmith and Danny Elfman (she was part of the team working on The Nightmare Before Christmas) and uses her mainstream paychecks to finance labor-of-love independents, such as an upcoming operetta / tone poem with a working title of "Three Pigs."

This genre is more complex than, say, a board book, but some of the same concerns are played out: "This kind of started because of my putting a video of pigs on the internet and response I got," she said. "It wasn't even showing slaughter or anything, it was mother pigs gnawing on the bars of their cages to try to get out and rescue their babies." While some who saw it said "'wow I didn't know,'" Cavallari said, "Some people were so furious with me, you know, 'Mind your own business, calling it 'animal porn.'" She added that "we want to eat what we want. but we don't want to know" its backstory.

Yet that backstory is the point of vegan messaging, restoring what Carol Adams has called "the absent referent," which makes it harder for people to pretend no one has been harmed by their choices. At least Cavallari has a full quiver of artistic skills to make that troubling message go down easier.

The piece, which she expects to finish around the first of the year, will focus on "the horrors of a pig escaping a truck on the way to the slaughterhouse," employing an orchestra and the singing of "people playing pigs," she said. "It will have elements of projected images ... and sound effects, I use a lot of sound effects in my music." Pushing the envelope further to "communicate consciousness," Cavallari said she's considering finding ways to include smells as part of the experience.

One would be "that terrible animal smell" of slaughterhouses, she said. "On the road from San Francisco to LA for a 15-minute stretch you can't open your car windows because of the noxious gas! But also to create smell of what the earth should be." She's hoping to "hit them with all the senses," since art "has a way of navigating issues, of affecting people in a visceral way." The point won't just be about pigs, but about how we can "rise above all the obstacles in our way by working together. Hopefully, everyone walks out with a great feeling."

Using the visceral power of music and multimedia to carry a vegan message is also part of Michael Harren's goal in The Animal Show, a hit in Houston, Los Angeles, Berkeley, Portland and NYC finally making its way to Philadelphia. Harren's format combines his prodigious keyboard skills (he's toured with Sandra Bernhard as her pianist) with humor, songs, video, found sound and "straight-up storytelling" about his own vegan life and his time spent with animals at sanctuaries and elsewhere (including rescuing live chickens from the infamous Kaporos ritual). An onstage string trio accompanies portions of the performance.

Harren said that the common thread throughout all the variations in tone and medium is his own "inner journey from working with animals" but that the underlying point is "showing animals as individuals trying to stay alive." The show has a director, Adam Fitzgerald, whom Harren credited with helping navigate some of the tricky areas discussed above.

"At one point he was telling me, you're being too 'nice,'" Harren said, so he has taken the gloves off here and there - at one moment near the end "I do actually get 100% preachy, but I've earned it with stories."

The emphasis on animal personhood derived partially from his residency at Tamerlaine Farm Animal Sanctuary. He described watching a rooster who was "too big a bully to be with regular roosters," but not big enough a bully to hold his own against the roosters in the "frathouse." He just didn't quite fit anywhere, and Harren realized that rooster's struggle to figure out where to go resonated with "my struggle as a kid being bullied for being gay."

Since many of us of whatever stripe have been bullied as kids, that experience can serve as a bridge to empathy. Speaking of one former colleague moved to stop eating chickens after seeing "The Animal Show," Harren saw him make just that connection: "Oh [no], I'm doing something here that people used to do to me."

So board books, regular books, one-acts, symphonic oratorios, any number of artistic genres can play a part in opening the public's eyes to the reality behind veganism. And while there's no surefire method for awakening people who eat animals to the animals' individuality and interests, judging from the response, Harren may have concocted a winning formula, while at the same time keeping vegans entertained.

The best art has a way of widening our worldview and, in these cases at least, helping to extend our circle of compassion, no longer stopping at the barrier of species. Yes, when we say "this show has something for everyone," we really mean everyone.

Michael Harren, The Animal Show, The Rotunda, 4014 Walnut Street, November 16, 8:00 p.m.  Tickets: $10 advance / $12 door