I started the duck house this weekend. I am going to add a feeding area to this. My question is what should I use for the run area as I don't want it to be mud? I thought I read wood chips are not safe for ducks? Also the run area is 4 feet wide by 6 feet long (house is 4x4). Is that enough room for 4 ducks? They will be free range most of the time. This will be used at night and when we are gone for a weekend. Also we are getting 4, 2 for each kid. I was wondering about tagging their legs so they know who's is who's. Would little colored zip ties be a bad idea? Thanks! (did use some old tin off an old barn on our land, thought it would be neat to tie like that into my duck house).