try giving them some roughage.... dandelion greens, spinach, grass something like that. My chicks love it when I pull up a dandelion plant roots and all and hang it into their cage. They go nuts pulling on it and chasing whoever gets the biggest piece.
when I raised meat birds, cornishx, I noticed more stink. I was told because they eat soooo much more they do not digest all thier food. It is actually the undigested food that stinks bad. If you were to wet some of the food and leave it out you would notice it smells just as bad! Maybe your...