I do not see that in the terms of service. There is an faq that points out that the site relies on ads for revenue.Since BYC's policy is against ad blocking software, it would be prudent to take this discussion into a private conversation.
The purchase of a PFM will remove ads from the site.
I have a premium feather membership so do not see ads here
@Aria This might get you to the place for premium feather add on: https://www.backyardchickens.com/account/upgrades