Survival estimate equals 0 in robust design

[Klop]

Hello, I have been running robust design for a mark recapture study, and have found that for all of my models where survival is varied by time [S(t)] there are a handful of time periods where survival = 1. My time periods between intervals are >1 month, so I wouldn't expect survival to be 100%. Also, my deviance for all the models = 0. Does this mean that something has gone completely array? Am I still able to use these models?

Thanks very much!