Are they eating their eggs? That would be the only problem I could see with that situation. seeing them as something to be exploited for what they make, rather than as individuals.

Whenever I wonder if something is abusive, I just compare it to what it would be like if they were a human. If there was a human woman in your care with the same intelligence of a chicken, you wouldn't think it was okay to milk them and drink their milk. That would be fucking weird.