There is a chance you might still be eligible for B.Sc. (Hons.) Zoology in DU with a failed Chemistry score in CUET, but it depends on a few factors:

Each program at DU might have a minimum marks requirement for each subject in CUET. You need to check the specific eligibility criteria for B.Sc. (Hons.) Zoology at the colleges you're interested in on the Delhi University website.

Even if you meet the minimum marks requirement, admission depends on the cut-offs for the program. Since you failed Chemistry, your overall CUET score might be lower, making it more challenging to secure a seat compared to students who scored well in all subjects.

https://university.careers360.com/download/ebooks/all-about-cuet

I hope it helps!