Hmmmm, it’s hard to know. Those poops don’t look so huge that they raise strong alarm bells for me, but it is something to keep an eye on. If she continues to have chronic stasis issues, then Megacolon could be at play.

With them being only 3 months old they should be getting more pellets. Many recommend unlimited at that age. If she is a megacolon bun, some people have also found these bunnies do best on an unlimited pellet diet. It sounds counterintuitive, but megacolon bunnies do not have a properly functioning cecum, so they have trouble keeping weight on, and the constant supply of high nutrient food helps them.

This page is one of the most detailed sources I’ve found on megacolon:  https://www.vgr1.com/megacolon/

Keep in mind that even if your rabbit has the double En gene, megacolon is still quite rare. Rather than worry too much over it, it would be good to track your bunnies weights (they should still be growing), keep feeding a good diet, and keep it in mind if you start seeing more symptoms (chronic stasis/gas, more huge egg shaped poops, weight loss and muscle wasting). The diet right now looks good, aside from the low pellet amount. Ensuring good hydration is also important.

Also, I’m obligated to mention that young bunnies are often mis-sexed and then you can end up with unwanted pregnancies. Bunnies can also start fighting when puberty hits, so be prepared to separate them until they are spayed if you notice any sort of hormonal behavior (would be good to check for testicles regularly, just in case) or fighting.