So they are about 5-6 weeks old. When do I change their feed and any brand recommendations? preferably something I can get from online like Amazon. Right now they are eating Dumor 20% Chicken starter grower & Dumor Organic 19% starter grower. I'm not sure if the percetage makes a difference but I was running low on the 20% one and I could only find the 19%. Also when can I introduce veggies and stuff.