Not only your young girls may lay very irregularly.. they may lay odd looking eggs to start with.
Be prepared to see very, very small eggs or funny shaped ones or without yolk or even without shell =leather eggs. All that is 'normal' with young girls and will usually normalize after few oddities. They just have to get their system into right 'gear'
What KT said about bread is very true...and same apply any 'treat' foods... potatoes, pasta, wheat/mixed corn.
If you supply your girls with layers pellets/mash as their main food ..
anything else is just a 'treat' and the girls will lay well for you.