Why does Mrs. Arable suggest Fern sell Wilbur to Uncle Homer?

Fern loved Wilbur more than anything and she took care of that pig. He loved her too and followed her wherever she went. Wilbur was growing bigger and Mr. Arable said they can no longer keep Wilbur since shes growing big. Mr. Zuckerman agreed to take Wilbur into his farm.

Because the pig will grow up and take up space and make a mess and they don’t want Fern to embarrass them with her pig.