They can take their time at first, and then some will lay like crazy for a couple of weeks, an egg every day, and take a week off. Make sure they have some extra oyster shell available, plenty of water, never let food or water run out -- that can stop egg laying cold and even send older birds into a molt. Your young girls might not molt for a year, but this is the time of year chickens start molting and then they do not lay for a while. The colored egg layers sometimes lay less, but live longer than your ISA Brown.Thank you! Yes I am a first time chicken owner and loving it!