I am surprised your new birds even looked at what you offered them. Mine are 3/4 turkey vulture and eat anything we throw on the ground. We are afraid to fall outside as we know we will be devoured in seconds.
Also my chicks have a learning disability. I use self filling dog dishes during the non-winter months. They work great, I just have to move the hoses when I mow. BUT moving hoses twice a year is no biggie.
I had one bunch that had a barrel with the littel red drinking cups that I just filled with water when they needed it. Last Sunday I moved some birds to a different pen, I now have my pullets and roosters kind of separated. The ones from the water cup pen refuse to drink from the dog dish. The stand around the water cups and keep trying to get water from the empty barrel. They will die of thirst before they try the dog dish..........
I gave up yesterday and put a livestock float shut off in the barrel for them....
I am planning to start the heavy cull in a week or two. Any cockerel with a defect is headed to freezer camp. The pullets will be fast behind them. I will be to 50 by Oct, not counting the chicks I am test breeding or the toads.