I would say she is not a bantam... too big.
I'd assume a leghorn, although I can't tell from the picture.
And if she's still growing, she probably will start laying soon... She's probably young.
Nice coop you built. Funny how a "free" chicken quickly turns into a money pit!

I think Liberty needs some girlfriends to yak with. My girls are always carrying on about something. Now they come find me to tell me the latest gossip from the coop.
I think Erin's right--not a banty breed, but a small standard size chicken.
When you said she fell off a truck, was it a truck that was transporting hundreds of other chickens? If so, she is only 12-16 weeks old.
I really do think she needs a friend or two. They are flock birds and worry if they are all alone. No one to keep an eye out for trouble if she has her head down eating.
Good dog Cassidy!! Not eating the chicken!!
Carla

That's a nice coop! Looks like a good set-up, lots of green grass.

I agree with the other posters, Liberty would love it if you got her a hen friend or two.

Oh yeah, my first were 4 "free" chicks someone gave me for my 2 year old son. $100 pen, additions to the shed, umpteen more chickens, 7 years later.... I love MY chickens :0)
my son... well he can take it or leave it. The darn birds take too much of his "mommy time"