User blog comment:B214/Chapter 383 Surfing Lucy thoughts and analysis/@comment-220.255.101.99-20140509140545/@comment-7418318-20140511091838

That depends...

It was stated that Layla's body couldn't take the strain of being a mage, forcing her to retire.

If this is the truth, her summoning three Spirits at once just to say goodbye makes no sense at all. She could just summon them one after the other and thus reduce the strain on her body by a fair margin.

So unless it turns out that her weak body was just an official excuse and the true reason was something else, I hope Mashima will either reveal that it was the three care-takers that summoned the Spirits or keep it as it is, without any definite answers.