If there is one thing that Lyddie is good at, it is working hard. In chapter 1, readers can see that Lyddie carries the majority of the work around the house for her family. Once her mom leaves, Lyddie and her brother take on the entire farm themselves. This means that Lyddie and her brother are putting in some long hours, but there isn't exactly a quote that specifically mentions the hours that she is working.
Chapter 3 has Lyddie working at Cutler's tavern. Once again, Lyddie is put into a position that requires her to work herself to the bone. She is at the owner's beck and call and has to do a ridiculous number of chores to help keep the tavern working and clean. Readers are told in the final few pages of the chapter that Lyddie worked very long days.
She was ordered to bed lat and obliged to rise early....
Unfortunately, readers don't get an exact count of hours that Lyddie is working, but it is clear that she is one of the first people up and the last people to bed.
If you need a quote with an exact number for the hours that Lyddie works, then you need to look in chapter 9. The quote is on page 70 of my edition, and the quote comes from a conversation between Lyddie and Diana. Diana is helping Lyddie get acclimated to the factory work, and Lyddie states that she is used to hard work. Diana mentions to Lyddie that a thirteen-hour day probably won't feel long to Lyddie, and Lyddie basically responds that thirteen hours per day gives her time to herself in the evenings.
And I don't suppose you think a thirteen-hour day overly long, either.