Four Chicken "tweens" 8 wks old in coop/need ideas on fencing to allow them some addtl space

I have four, hopefully hens: a Red-Sex link, Buff Orpington, Australorp, and a Light Brahma. They have been outside in their coop now for about 10 days. They have a ladder up to their roost area which they won't go up on their own. I have to put them up there one by one each evening and then lock the door (which I added). I should note I am brand new at this. I've never owned chickens before. I wanted pets first then eggs (my husband wants eggs and has been willing to go along with my perhaps cockeyed dream). So I did a lot of research before I got them but now have more questions. I wanted 3, I read up on breeds that are "known to be friendly, quiet, and lay a decent amount of eggs." My husband chose the red-sex link after he read they're egg producers. She was number 4....

We added wheels to the end of one side of the coop, still it takes two people to maneuver. I've had my husband help me move it twice. There is a lot of chicken poop in the bottom of the coop and in the extension we added. Do I put down pine shavings? I hate to do that because my husband wants an area of grass in the backyard. By the way, when I turn the sprinklers on I've been rerouting the sprinklers that hit the area of the chicken coop (can chickens get wet?). I'd like to allow the chickens to get outside the coop, but what fencing can I put up easily so I'd be able to move it, if there is such a thing? Any advice regarding any or all my questions is appreciated!!