Those are pretty good guesses on ages.
First one - treated with herbicide and planted last winter?
Second - 2nd year after planting
Third - I love this cut. Full of groceries, but not enough cover to hold a bunch of deer all day. Does will stay in there all day if no one walks through it frequently. There should be lots of deer using this cut at night. This one will likely be really good next year, and for at least 3 -5 more years depending on whether or not it has been planted. It may be that it just wasn't treated with herbicide, which is a big plus for hunters.
Fourth - I count 12 years on the trees in the foreground. Central right looks like it may be a couple years younger.
You can age the cut from the date of planting by counting the whorls on the fir/Doug Fir. Each major growth of stem between whorls of branches is one years growth. Many industrial forestlands are cut, herbicide treated the next summer, then planted the following winter, or the winter after that. You have to judge the quality of the cut for deer hunting based on the amount of space left between the trees to grow food and also how well you to be able to see deer in the mix. Fertility of the soils determines how fast the trees grow and how fast the space between them disappears and no longer grows deer food (under dense shade). This varies from area to area, so the age of the cut is all relative when it comes to hunting, but once the canopy is closed, the unit is good for cover but bad for food (and hard to hunt).