Welcome!
Trimming, what is called "trimming" (debeaking) are two different terms that are often used interchangeably.
Trimming if just the tip outside of the beak's "quick" so to say where no blood or bone is reached is sometimes done to show birds or birds who do not have access to the soil to naturally wear away their beaks.
Debeaking is a practice often hotly disputed, and is usually only done in high density layer operations to keep the birds from picking each other apart due to boredom. It doesn't change egg laying.
If you are raising a backyard flock with ample room, you shouldn't need to do anything for their beaks.
The space requirements are all guidelines. Guidelines say 4 sq feet inside the coop, and 10 sq feet in the run per bird. However, tractors that move weekly or even daily get away with less, and bantams get away with less. A 10 ounce banty doesn't take nearly as much room as a 14lb cochin.
Some say you need 2x this room or more to keep them happy, but it also depends on what is in their living establishments. 100sq feet of plain brown dirt is not nearly as stimulating as 100 sq feet of underbrush or your freshly planted garden they decided to dig up and destroy for you. So if you can keep them mentally stimulated, you can probably get away with less space per bird. However, it is always easier to prevent rather than cure problems with chickens.
As for where to get chicks, try a hatchery. Places like Ideal (TX) still have some, but your biggest selection will be in the spring with production ramps up. As for adults, you'll probably have to post locally to find some in your area. If you do bring in adults, I'd suggest searching our forum concerning quarantine times. Quarantine of adults can save you A LOT of headache if you catch a potential problem before bringing it to your flock.
Best of luck and enjoy!
