Quite possibly. In the spring, summer and fall when they're eating a lot bugs and whatever else they find on the ground, the eggs are tougher to crack. In the winter when they stay snuggled up in the coop out of the cold and are eating a lot of sack feed the shells are thinner.
Another thing they love is oyster shells, they're rich in calcium and they love them.
There are chickens raised near by. A few months ago, they made a break for it, down the same path I described. I only saw a duck family quacking in the pond yesterday. We do have lots of big geese honking around. The guy could have just walked a few yards into the woods and dropped the pumpkin. Lots of deer, racoons, etc. would have had a Thanksgiving.
Luckily the local bear hasn't been seen lately. Probably read about his compadre who was shot in 2018 for walking down a street too many times.
Something (raccoon most likely) broke into neighbors pumpkin. Then the red squirrels moved in. They had over watch set up in the tree and active miners inside. They held off all comers for three days and consumed the whole thing.
Chickens need calcium in the diet to produce hard shells. Some feeds have more calcium.
We give our chickens pumpkins as the fiber is a natural wormer. The only thing left is the rind. Cornbread with cayenne pepper is also a good wormer. In the summer, we toss watermelons out to them. Keeps them hydrated and a bit cooler.
We do not waste much food as what we do not eat the chickens typically do. The gristle from steaks, leftover veggies, extra biscuits -- it all goes to the chickens as supplements to their usual feed. The eggs we get have very hard shells and the yolks are a deep orange, not a pale yellow.
We put our leftovers on a big rock down near the edge of the front yard and feed the wildlife. My wife watched a Bobcat run up and grab a whole chicken carcass and run off with it. We also have racoon, possum, skunk, fox and others. Not many vegetarians though. Lettuce etc just sits there and rots.
I wouldn't call common store bought yolks yellow, but I've noticed that my son's chickens put out eggs with darker yolks. I just thought it was because they ran around the yard instead of being in a barn with thousands of others.
According to this, also better for you: https://healthyeating.sfgate.com/nut...eggs-1163.html