I've never known roosters to help much in the protection department. They will call the hens over if he finds a tasty bug or worm. But they tear the hens back up, especially if you have more than 1 rooster.
I have received many boxes of baby chicks over the years, mostly raised them with the Heat lamps (100 watt was sufficient). For the last batch I made two changes. First, I bought a Brinsea heating plate. Set it up level for several days, then switched to Tilted. I love this as the heat is...