SOLVED. Kids get abandoned by their parents at a fast food place [s]

[Ana]

Four kids, 2 sisters and 2 brothers (I think), get abandoned by their parents at a fast food place during one of the sister's birthday. The kids are forced to manage by themselves. They live for a while at a crop field, where they catch lice. Then they are found and transferred to an orphanage. Their father was a criminal and their mother always neglected them. At the end of the book, the oldest sister (or one of them) opens an orphanage to help kids.

I'm not sure when the book was published, but I'm guessing 1970s or 1980s because my mother first read it during elementary school, although it could be older.

It is NOT "The Homecoming" by Cynthia Voigt.

[Ana]

The book is set in the USA.

Also there were four kids standing in the middle of the road on the book cover.

[Lobstergirl, au gratin]

Is it aimed at children, YA, or adult?

[bookel]

Three children ...

A Long Way to Go by Borden Deal
What happens when three children spend the day in the supervised daycare program of a Florida resort motel, but at the end of the day, their parents don't come to pick them up? The motel manager and the uncaring-caregiver want to "do something with them," and the children fear the worst. So the next morning, they just leave the motel and start walking home. Home is six hundred miles away, which leads to an enthralling story of their trip, the people they meet, the ways they find food, frightening experiences, and their worry about what has happened to their parents.

Under the Haystack by Patricia A. Engebrecht
Three sisters, abandoned by their mother, try to keep the truth from the neighbors and continue to operate their farm.

Four children ...

Stay tuned by Barbara Corcoran
En route to stay with a relative she has never seen, fourteen-year-old Stevie meets three other young people with no place to live and takes a detour with them into a new life in the New Hampshire woods.

Five children ...

Broken Promise by Alex Lazzarino and E. Kent Hayes
Abandoned by their parents en route to California, five children (the oldest 11 years old, the youngest 18 months old) learn to subsist on their own and to defy a juvenile court system that threatens to separate them.

It is the last book. There's mention of bumps on the head, scratching them.
Kirkus Review for Broken Promise
" ... abandoned by deadbeat parents at a highway hamburger joint, ..."
Don't mind Kirkus Reviews, they're often harsh. It sounds like a good story.
It can be borrowed free from openlibrary.org (search Hayes Broken Promise), or see abebooks.com or bookfinder.com for secondhand copies.

[Ana]

It's "Broken Promise." Thank you very much!

[Kris]

Glad you found your book, Ana. Here's the Goodreads link - Broken Promise by E. Kent Hayes & Alex Lazzarino.