I have a combo. I have 4 6x10 pens on concrete with block between them so they cant see each other unless they are in the boxes looking out or on their hind legs, cuts down on fighting and barking when i have females in heat and Puppies with a nursing mother so she does not get stressed. The boxes built on the back so they have the whole area . The entire kennel under roof with my feed in a drum at the end. I bleach the kennels once a week and clean the water buckets a couple times a week. Concrete is easy to keep sterilized and zero flea problems and cool in the summer when shaded. I feed in the evenings when it cools down and hose out everyday, that is a Must. I also spread lime once a month behind kennels. I have 3 dogs on axels with 12 ft chains. They can get 360 degrees and not get tangled and stay muscled up and in good shape. All have dog houses are under trees with shade. Doing flea pills this year for the first time ever due to the dry year and the problems. I like to alternate dogs from the chains to the kennels. helps keeping them is shape and their nails nice and short. Ivermectin every month on the first day, 7-way booster shots every Jan with rabies shots.. Feed Diamond Hi-Energy and Raw chicken and Jack Mackeral depending on whats going on.