I think you could keep them on the egg yolk for up to a week but probably not much longer. Then they really need more than what they will be getting from the fat in the yolk. The extra nutrients found in the liquifry and the First Bites will help them develop and mature and are really needed so unless you are severely hampered from getting them I think the fry really need one or the other after day 7 but I am in total agreement that the preferable day would be day 5 to actually start the changeover to other foods they really need to be weaned off that egg yolk sooner than later.

Rose