I presume these were potted growing bushes?
It sounds as if the soil fell off the roots when you removed them from the pot. In the process, tiny feeder roots that are the only source of moisture are also lost. Until these feeder roots grow back your bush will show signs of stress. Water daily and deeply. I set a hose on tricle and let it run at the base of the bush for at least an hour daily until the bush shows signs of growing. In poorly drained clay soil, you shouldn't water as often but deep watering is inportant.
All Knock Out roses are notorious for quickly fading blooms so this is something you'll have to live with, although the wilting and drooping is a contributing factor.
There is a way to plant a potted rose that eliminates the loss of feeder roots.

Planting a potted rose
When planting a potted rose bush, care must be taken so soil doesnt fall from the roots or tiny feeder roots will be lost causing the plant to be stressed.

I overcome this problem by doing the following.
First prepare the planting hole. Dig it twice as wide and deep as the pot. In the bottom portion of the hole mix horse manure or an organic fertilizer with the soil.
With a sharp razor knife I cut the bottom from the pot. I then cut down the two opposite sides of the pot about two inches. Using masking tape, rubber bands, or string I secure the two cuts then continue cutting the sides to a point halfway down. I secure these the same as the top cuts were secured.
Holding the bottom, place the pot into the hole. If the bush is a grafted plant, position it so the bud union (swollen knob/graft point from where the canes grow) will be 4-6 inches below the soil surface in cold growing areas. If the bush is on itÂs own roots, position it so itÂs no more than an inch deeper than in the pot.
Slide the bottom from the pot. Pull soil into the hole until it come to the lower tape/rubber band/string. Cut the tape/rubber band/string on both sides of the pot and continue filling the hole to just under the top tape/rubber band/string. Cut the top tape/rubber band/string and fill the hole so just the tops of the two pot sides are above the soil. Pull them straight up and complete filling the hole.
Do not tamp the soil. Settle it with a hose set to just a trickle so all the water stays on the soil around the bush. There should be a depression around the bush. Add more soil until most of the depression is filled. Until the bush is growing well, water daily soaking the area well.
Planted this way, the bush will not know itÂs been transplanted and should show no signs of stress.
When watering, make sure you apply enough so it gets to the roots. A light sprinkling only wets the surface. This can cause the feeder roots to grow towards the surface. In dry spells the bush will wilt. Watering deep eliminates this problem and causes the roots to grow deep enabling them to better withstand periods of no or little rainfall.
A five gallon bucket with a 16D nail hole in the bottom side and filled with water, then placed next to the bush will supply the needed water with no runoff. All the water will soak into the soil at the base of the bush.
In sandy soil do this daily until the bush is growing well. In clay soil, do this when the leaves show signs of water distress but at least every other day until itÂs growing well.