Large Egg-Shaped, Oval Poops

Hi all! About a week ago, I adopted Hako from a rescue. He is a lionhead-ND mix, estimated to be 3 years of age.

Today, I noticed that his poops look really egg-shaped and oval. They are quite big too. His diet consists of APD High Fiber Hay, Oxbow Essentials Adult Rabbit Food, and vegetables (chye sim, xiao bai cai, nai bai)

He has been in a 'loaf' position a lot too, I'm not sure if he is just chillin or in pain perhaps? In the top pic is his 'rounder' looking poop, bottom is his poop today. The gold coin has a diameter of 16.75mm, the silver is 18.50 mm. Should I be concerned?

Thankful to have this community guiding me through!