Even though you live in a wooded area with an open yard, these Greys will target wherever the heck they want to- some have had encounters with them in very populated city areas at night too.
They are said to have a "hive mind" so that may be why they were walking in step with each other .
From some of the testimonies I've read, some have actually had angelic intervention chase these Beings away-- seems they aren't in line with the Creator- and they are said to work with another alien being (reptilian) which makes me NOT want to be too quick to run under a hovering UFO if I see one..lol (yikes)
I feel that just as we humans abuse and over-exploit this planet, these Beings have thier own selfish agenda here as well.