this is what i do with my y/bs ,i feed them well plenty of waste until they can fly about 6 weeks , then once they start going out they only get out at night well after 4.30pm i give them a light feed in morn ( 7.30 am)usually g10 pellets and some hormoform mixed in then they get out later depends when i get home from work this varies , but after flying at night they usually get as much as they want , but once called to get in they have 30 seconds for all to get in after that trap is closed till food is gone then the ones that did not go in ,go in when they want but get no food ,the next morn the ones that did not come in the night before get separated and not allowed any food , they are usually the first in that night ,but some are very stubborn usually the hens (just like the wifes) so do the same again till they learn . my birds are usually never starved but have to obay me or else .