Mobile development -- 2

I need an iPhone app. I would like it designed and built. i am looking for someone to help me design an app that allow me to help me count boxes in my packing shed on my strawberry farm. i have a strawberry farm and when we employ hundreds of workers working to pack our strawberries we need a system that would allow us to count each box that each employee have completed. our current system. we have each employee take a box full of punnets there are 400 punnets in each box. each employee will collect their box at the box station and mark the time they took it. when each employee finished their box they will then come to the station and mark the time they finished it and we will get the tally of how many boxes they finished by the end of the day and by the end of the week. ready for payments. but we have to do this for 200 hundreds workers so we need an app for this.