If the crop is hard in the mornings, then I would first begin with the coconut oil twice a day, massage the crop several times a day. Re-check first thing in the morning.
You may need to do this for a few days. If it doesn't resolve, then go with the next step of coconut oil and a stool softener. Try that for a couple of days. If no results then you may need to give her a flush.
Crop issues can take days to resolve, so keep at it, but be patient.
Sometimes there's something else going on that is making it slow to empty - things like worms, reproductive disorders, coccidiosis or infection, but give her several days to see what happens before you consider any other treatments unless she starts acting sick.