Let $S$ be a connected noetherian normal scheme of dimension 0 or 1 (i.e. $S$ is a connected Dedekind scheme).

Let $f:G\to G'$ be a morphism of semi-abelian schemes over $S$. In their book on Neron models, Bosch-Lutkebohmert-Raynaud define that $f$ is an isogeny if for all points $s\in S$ the base changed morphism $f_s:G_s\to G'_s$ is an isogeny (i.e. $f_s$ is finite and surjective on identity components).

Is $\deg(f_s)=\deg(f_{s'})$ for all $s,s'\in S$?

If this is the case, can one then define the degree of $f$ just by $\deg(f_s)$ for $s$ the generic point of $S$?

If the above questions have negative answers, can one answer them affirmatively for abelian schemes?