I have been raising chickens for quite some time and have gone through many "live and learns"... Chicken wire is useless. It's meant to keep poultry in and NOTHING out. I have built my pen with hardware cloth on the bottom and welded wire for the remainder and top. Make sure there are NO gaps...
About 1.5/2 months. The last 3 purchases I made of them (Long Island, RI, and NJ) before this have all been about same age and $25 each. But I can sell goslings in CT for $100 breeding pair Bc they are hard to find. Good luck with yours :)