planted a laurel hedge

I planted new laurel hedge about 2-3 weeks ago about 100 plants all looked good and healthy but 5 -10 of them have started to turn yellow and look like they are dying, some leaves look very limb unhappy. watering several times a week not sure was it the frost or over or under watering are am i just doing more damage than good also unsure what manure to use some one suggested chicken manure…