Behavioral differences in my dogs?

Question

i have four dogs of my own. we have more at our house but i only consider 4 completely mine. (i pay the vet bills, food everything for those 4 dogs)

two of the dogs, the girls.. i can let them roam in our yard (we dont have a fence for the front) and they listen to me perfectly. they dont go into the street. of course, i only let them roam when im out there with them.

my other two dogs cannot be without a leash, they will try to leave the yard all the time. they wont mind me at all. they are both boys.

i do keep the boys on the leash all the time when i take them out. i dont know if they simply dont mind cause they are both boys? i dunno. my girls mind me very well.

the 2 boys:

http://www.flickr.com/photos/28942901@N08/2779161023/

http://www.flickr.com/photos/28942901@N08/2722697237/

the 2 girls:

http://www.flickr.com/photos/28942901@N08/2772597197/in/set-72157606841732561/

http://s129.photobucket.com/albums/p215/zoomer1011/?action=view&current=DSCF3819.jpg

Answer 1

Are they neutered? Especially if you have other females in the area, or people who may have the smell of female dog on them, males can become very distracted very easily.

Answer 2

some people say if you nueter  them they will be more calm but i dont believe it i have a nuetered pit bull and hes always never minded anybody and my lab hasnt been and he never listens either lol good luck just let them know whos boss untill you trust them you should keep on a leash : )

Answer 3

what breed are your boys? i have one thats almost identical to the 1st boy. hes a lab/shepherd.