I had a similar run for my coop and ended up replacing everything. First, chicken wire isn't predator proof, but if you lock them up at night they will be fine as long as you don't have any vicious dogs around. That said, we had many weekends we were gone and switching to hardware cloth allowed me to leave the ramp open and they could let themselves in and out as they pleased. Also, I didn't have to get out of bed every morning and let them out right away.
I think it will be too small for as many pullets as you have unless they are allowed to free range during the day for a few hours. I also recommend staining it if you want it to last a few years. Can't tell by the picture if it's stained, but it looks like it might be raw wood. I would rip that chicken wire off, stain it, and replace with HWC.
I also figured out pretty quickly that I got tired of moving everything and it weakened the nails / screws to do so. I ended up building a door on the end of it so I could clean it out easier.
Later in the summer, rats and mice started digging under to eat the chicken feed. Dangerous on many levels for chicken health. Then came the flooring. A skirt works too.
Then came the rains and on went the roof. The rain splattered the bedding material in the run and on went the plastic floor runner on the side *sigh*
Hope this works better for you than it did me. It was a lot of retrofitting, but now I love it!
All said and done, I ended up buying a new coop about 9 months later and only use this coop and run as a grow out coop.