don't bother with rocks, the hens will just dig them up. Use hearty metal lawn staples and just use them to tack the cloth down. The grass with be up and through within two weeks. The thatch will totally cover the wire within a season.So very sorry for your loss! I am hatching eggs as we speak and 10x30 pen being built, we ended up spending the extra money and got hardware cloth, i was abke to find it on amazon for $280 i got 2 rolls of 4ftx100 1/2 holes, it is really nice...free shipping got it in a few days! I know price is still high and thats the cheapest i found and looked for months, but its worth it to do it right the first time! we are also laying foot wide pieces alomg the whole bottom on the outside to avoid digging in, im not burying it but attaching to the bottom piece of wood securely, same as burying it but easier, worls the same way, i may even cover all that with ornamental rocks for looks and extra security, i deal with the same predators you listed and we are new to our area (1year here) so we havent experience it yet..add 1 hawk family and an owl family that live here as well! My neighbor gave upon chcikens we are just beginning, but mine will not be free ranged unless we are here to watch them!