I will be getting an 8-week-old Lab soon. Should I feed it Perference. Also, should I be adding calcium to the diet?

Hi, I am using Preference for my 5 yr. old Dogo and my 8 yr. old Golden. I will be getting a Lab puppy about 8 weeks old. Should I use Preference and does it have the right ratio of calcium and phosphorus? Dogs can develop a bone disease when the calcium/ phosphorus ratio is disrupted. I always add beef meat and pork and sometimes chicken. I do cook the meat. Should I be adding calcium to the diet? I do give them yogurt add vitamin E and eggs a few times a week. They also get Acai & Goji juice. They also get Standard Process Dermeral supplement because of their allergies. The dogo can't eat any feathered meat or white fish or peas or flax seed. The golden can't eat rice, eggs, white potatoes, milk products. I have to cook two different kinds of meats because of the food allergies so it gets complicated. The breeder of course wants me to feed Canda, I think that is the wrong spelling. I just went through my two labs passing away last month. They were 13 & 12 but I think if they had been on a good diet earlier they may have not died of liver cancer. I am really trying to learn everything I can to be the best owner I can try for. Everyday I learn more. Thank You, sorry this is so long!

Judy