Don't worry, they won't choke unless you give them too small a piece, like a chicken neck or wing. If your dogs are gulpers, try for at least a leg quarter. If not, a drumstick is probably ok. Also, don't be worried if they chomp, chomp, swallow, and then yak it back up and re-eat it Gross, I know, but this is fairly common in the beginning, until they learn to chew properly.
You can go with the ground commercial mix, but it is likely more expensive and you won't get the teeth cleaning benefits.