Please look at this I need help with chickens?

My great grandpa says we can start a little chicken farm. So I need websites or answers or facts. If it's almost Summer is it to late in the year for chicken raising or hatching? How do I make a chicken coop for at least 20 to 25 hens? How do I keep coyotes, mountain lions, and owls away? When do they start laying eggs? How long does it take for them to hatch? How much should it cost to make a chicken coop? Thanks so much!