new layers- laying while roosting

I have 4 red hens that are about 18 weeks. We have had 1 egg per day for 4 days, so I don't know if we have 1 layer and the others are still maturing. Anyways, the first 2 days, the egg was under the ramp going into the coop and the last 2 days, the egg was smashed under the roosting spot. Thle last 2 must have been laid early in the morning, or over night. I went out there at 6:45 and it was laid, smashed and cooled. I am not sure which hen is laying, although, I have an idea as one has a much redder comb and developed her comb a month and a half before the others.

I have 2 nesting boxes in the coop, with wood shavings and golf balls to try and train them. Do I need to put another nesting material in to encourage them to nest in the boxes? How to get this hen to stop laying while roosting?

The first day my 4 year old dropped our very first egg, we got to eat the 2nd, the last two were broken.... we are not having good luck with our eggs.

HELP.