I bought 27 baby Welsummer pullets & 2 roosters & i have lost 11 of them & i just can't figure out why they are dying off like this I have them on the 24% starter & grower they are only 3 months old we also have 7 Road Island pullets with the Welsummers the exact same age & not one of them have died I am just stumped what do you guys think?