How do I prune/shear a techny arborvitae to encourage growth

I had some landscaping done a couple of weeks ago and had a 9-10 foot techny arborvitae planted and it looks nice and healthy except when you get close up to it and see that it is thinning inside. When I look at the internal branches many are bare but I will also see small fans of new growth. I've read that you don't want to cut branches back to a spot where there isn't any green because then it will remain bare for good. My question is how far to I prune it back to encourage it to fill in? Will the small bits of foliage inside eventually grow to be branches and take care of this problem naturally? Everything says that this tree is super resilient, so should I just give it time? I've also read that evergreens will shed inside foliage in the fall, and I'm noticing a bit of this as well. Do these trees suffer from transplant shock of any kind or could the falling foliage be normal? Also, it has a ton of seeds on its branches, and I've read that overproduction of seeds may mean it's stressed. Do I need to worry about this? Thanks for any help at all!

I think you need to give it time to settle down and give it a good drink too, yes plants, trees etc can go into shock when transplanted, they have been nice and snug in the area and pot before they arrived at your place, sometimes even the travel from one place to another causes this and they loose foliage, but with good care, they usually recover well,
I have sometimes had to resort ot digging an empty clear plastic bottle into the soil, turned upside down and cut the bottom off, this way when you water the root area, you know the water is going down to the roots as sometimes when trees are planted and the planter uses their foot /heel to firm down the soil around the roots, it is too compacted and the water dont get down to the roots, runs off the top soil and we thing the roots are being watered and they are not, you remove the bottle when you know the tree is growing well and back fill the hole the bottle has left. I would say your tree needs time but do keep and eye on it ever week or so, everyday will give you a false idea of all sorts. good luck. WeeNel.

hi, well it is very common for Arbos to loose needles within the tree. Since you need sun for the needles to live. Arbos get very full and once they hit a certain growth point the sun is shaded out of the middle and the needles die. Also, every year around fll or earlt spring an evergreen will shed it's old damaged needles. In arbos they tend to collect and become a mass of dead plant material also adding to the needles going w/o sun. In these masses insects tend to dwell so that hurts them as well. So, this is what I do for hundreds of arbos in my business. I go through the trees and clean out all dead matter and dying branches, but only to the point of green matter. Basically get rid of all dead and keep all green. In older arbos when done it's going tolook pretty bare in the middle but don't worry w/i 1 year you will see lots of new groth up and down the fans. Fertilize in the fall because in evergreens this doesn't push new growth but pushes root growth.

Thanks so much for the responses!