I am considering getting a few dozen chickens for fly control for my 8 cows on 60 acres (I read they eat the larvae in the cow poop). This is in central Texas. The cows have an opened walled shed and the pasture has many large trees. I have never had chickens before. The main problem is I can't be there every day because my house isn't built yet and it's a drive. When I was mowing a few weeks ago I spotted many rat burrows, a coyote and a hawk. On another occassion I almost stepped on what I think was a Rough Greensnake (which eat insects). The coop (do I need one?) door would be open all the time. The perimeter fence is barbed wire, which birds can have problems with. I expect to lose chickens on a regular basis, but is the flock likely to survive or be wiped out? Should I have more roosters than usual for flock protection? Would the cows scare off predators? Will the chickens try to leave the property or tend to stay with the cows?