1) Make sure you use medicated feed for a couple months. I lost seven of my first fourteen due to cocci-whatever.
2) Get a storm door. They seem to think where you live is the source of all happiness and cracked corn.
3) They're not susceptible to Marek's, not by a long shot, but I've seen curly toe paralysis a lot so be warned.
4) Count them at night. Mine are pretty much pastured and their capacities for flight are surprising to say the least. A big problem with me is that my three original girls like to roost atop my BBQ.
5) Handle them a lot when they're young. That got neglected for me because of #1, and I ended up with fifteen chicks from Greenfire that never got handled at all. It was probably for the best considering mine have to stay clear of neighborhood cats and what-not, but if you're cooping yours up, you'll want them less wild than mine. That's not to say mine won't get in front of my legs and stop me from walking like a new puppy. It's just to say mine are impossible to catch or pick up.
I have to respectfully disagree with the recommendation to use medicated feed. Only use ampuprollium if there are signs of coccidosis. SFH are susceptible to a Vitamin B1 (Thiamine) deficiency. Ampuprollium effectively blocks the intake of thiamine. I have also had a vet who is a colleague in the Cream Legbar Club confirm the ampuprollium causes thiamine deficiency. This deficiency can cause curled toes and weak leg joints in susceptible/sensitive chickens.
After having lost a couple of chicks to cocci, I used to proactively treat all newly hatched chicks with Corid (ampuprollium). While that effectively eliminated concerns for coccidosis, I ended us with several SFH with severely curled toes and one with weak ankles and hips. I have found that cream legbars and cream legbar hybrids are also susceptible to thiamine deficiencies.
So as with any medication, use if it is needed. Otherwise don't! Your chickens, your call.