Sounds like they could be hot and want more space, and she's getting pushed out. I have a Cube as well, that I've had to modify to fit my preferences. It's frustrating to have to modify such an expensive coop, but here's some ideas you could try for very low cost.
1) If it's hot (I'd recommend a temp sensor in there to monitor it), swap out the 3 grey vent covers with hardware cloth. Just unscrew, cut the HWC to size, then reattach the cut HWC using provided screws and washers. Keep track of the vent covers - you'll want to add them back in winter. Like this:
2) Remove the nesting box divider to give them more space to sleep. It can easily hold all 5 with space to spread out on hot nights - if you take out that divider. You can add wooden roosting bars to give them a more natural place to roost. I have 4 adults hens in here (2 EE, 1 Orp and a very large barred rock). Not shown in this photo, but I even took out the grey bars and its even easier to clean now since no poop gets stuck between the bars. Like this:
3) Setup a nesting box in the shade in your well-protected run. You don't want them spending any time in the Cube when it's hot. It can easily get over 100 degrees in there. I have mine lay in a cat litter box in the run. Lock them out with the pop door first thing in the morning, then you can open up the back/egg doors to let in more air during the day. Spend your efforts keeping the run cool during the day, and then work on cooling the Cube down in the evening if you need to. If mine is over 95 at sunset, I take out the tray temporarily and hose off the *inside* which will cool it more than 10 degrees instantly (and dry fast b/c its plastic).
1) If it's hot (I'd recommend a temp sensor in there to monitor it), swap out the 3 grey vent covers with hardware cloth. Just unscrew, cut the HWC to size, then reattach the cut HWC using provided screws and washers. Keep track of the vent covers - you'll want to add them back in winter. Like this:
2) Remove the nesting box divider to give them more space to sleep. It can easily hold all 5 with space to spread out on hot nights - if you take out that divider. You can add wooden roosting bars to give them a more natural place to roost. I have 4 adults hens in here (2 EE, 1 Orp and a very large barred rock). Not shown in this photo, but I even took out the grey bars and its even easier to clean now since no poop gets stuck between the bars. Like this:
3) Setup a nesting box in the shade in your well-protected run. You don't want them spending any time in the Cube when it's hot. It can easily get over 100 degrees in there. I have mine lay in a cat litter box in the run. Lock them out with the pop door first thing in the morning, then you can open up the back/egg doors to let in more air during the day. Spend your efforts keeping the run cool during the day, and then work on cooling the Cube down in the evening if you need to. If mine is over 95 at sunset, I take out the tray temporarily and hose off the *inside* which will cool it more than 10 degrees instantly (and dry fast b/c its plastic).