diff --git a/src/builders.jl b/src/builders.jl
index a7123fb6..45316161 100644
--- a/src/builders.jl
+++ b/src/builders.jl
@@ -14,11 +14,13 @@
 abstract type Builder <: MLJModelInterface.MLJType end
 
 """
-    Linear(; σ=Flux.relu)
+    Linear(; σ=Flux.relu, rng=Random.GLOBAL_RNG)
 
 MLJFlux builder that constructs a fully connected two layer network
 with activation function `σ`. The number of input and output nodes is
-determined from the data.
+determined from the data. The bias and coefficients are initialized
+using `Flux.glorot_uniform(rng)`. If `rng` is an integer, it is
+instead used as the seed for a `MersenneTwister`.
 
 """
 mutable struct Linear <: Builder
@@ -29,14 +31,18 @@ build(builder::Linear, rng, n::Integer, m::Integer) =
     Flux.Chain(Flux.Dense(n, m, builder.σ, init=Flux.glorot_uniform(rng)))
 
 """
-    Short(; n_hidden=0, dropout=0.5, σ=Flux.sigmoid)
+    Short(; n_hidden=0, dropout=0.5, σ=Flux.sigmoid, rng=GLOBAL_RNG)
 
 MLJFlux builder that constructs a full-connected three-layer network
 using `n_hidden` nodes in the hidden layer and the specified `dropout`
 (defaulting to 0.5). An activation function `σ` is applied between the
 hidden and final layers. If `n_hidden=0` (the default) then `n_hidden`
 is the geometric mean of the number of input and output nodes.  The
-number of input and output nodes is determined from the data.
+number of input and output nodes is determined from the data. 
+
+The each layer is initialized using `Flux.glorot_uniform(rng)`. If
+`rng` is an integer, it is instead used as the seed for a
+`MersenneTwister`.
 
 """
 mutable struct Short <: Builder