Two females that were abandoned on the "streets". Both were pregnant. We made sure they had a safe and quiet indoor spot while I scheduled wellness appts, and we didn't realize they were pregnant. I rehabbed cottontails yet was unaware that domestic lagomorphs are self- induced ovulators and unless spayed their ability to have offspring happens year round. -- The first "mother" gave birth a couple days after her DVM exam to evaluate for ear mites, parasites (in fecal float), et al.
We knew something was amiss when Cuddles (1st captured agouti mother) became onery, territorial, and began pulling fur. The man on the street in the neighborhood said "many, many babies" born while hubby was in the process of capturing them.
Lurking predators: cats, vagrant dogs, skunks, opposums, raccoons, hawks, owls - some of the long list of predators - who will kill vulnerable infants, juveniles, and adults.